Basics of Image Editing: Tools, Techniques, and File Formats

Every photograph you see online, in a newspaper, or on a billboard has likely been through some form of image editing. Whether it’s a quick crop for social media or a detailed colour correction for print, understanding the basics of image editing is essential for anyone working in media, journalism, or design. This post covers the core concepts – types of graphics, popular editing software, essential editing tools, and the most common digital image file formats you’ll encounter.

Types of digital graphics: raster vs. vector 🔗

Before you open any editing software, it helps to understand how digital images are actually constructed. There are two fundamental types of digital graphics: raster and vector.

Raster graphics 🔗

Raster images are composed of pixels – tiny squares of colour arranged in a grid. Digital photos are the most common example. Zoom in far enough on any photograph, and you’ll start to see these individual pixels. The more pixels an image contains, the higher its resolution and the more detail it can display. A 640×480 image contains roughly 307,200 pixels, while a photo from a modern camera sensor can have over six million.

The strength of raster graphics lies in their ability to represent rich colour gradients, subtle tonal shifts, and photographic detail. Raster files show a wider range of colours and allow for more detailed colour editing, light rendering, and shading compared to vectors. However, their biggest limitation is scalability – enlarging a raster image causes it to become blurry or pixelated because the software has to stretch or interpolate pixels that weren’t originally there.

Common raster file formats include JPEG, PNG, GIF, TIFF, and BMP. Popular raster editing software includes Adobe Photoshop and GIMP.

Vector graphics 🔗

Vector images are created using mathematical formulas that define shapes through points, lines, and curves. Instead of storing a grid of coloured pixels, a vector file stores instructions for how the image should be drawn. This means vectors can be scaled to any size – from a tiny icon to a massive billboard – without any loss in quality.

Because vector images aren’t pixel-based, they are resolution-independent and can be resized without quality loss or visual artefacts. This makes them ideal for logos, typography, icons, and illustrations that need to appear sharp at varying sizes. However, vectors aren’t suitable for reproducing the complex colour blends and textures found in photographs.

Common vector file types include SVG, AI, EPS, and CDR. Software like Adobe Illustrator, CorelDRAW, and Inkscape are widely used to create and edit vector graphics.

Photo editing software: your digital darkroom 🔗

Photo editing software is where all the editing action happens. These applications range from free, open-source tools to professional-grade suites with extensive capabilities. Here’s a look at the most relevant ones.

Adobe Photoshop 🔗

Adobe Photoshop is the industry standard for raster image editing. It provides an extensive set of tools for photo retouching, compositing, colour correction, and graphic design. It supports layers, masks, adjustment layers, and non-destructive editing workflows. Photoshop is subscription-based and is part of Adobe’s Creative Cloud suite. It’s what most professionals in journalism, advertising, and photography rely on.

GIMP (GNU Image Manipulation Program) 🔗

GIMP is a cross-platform, free and open-source image editor available for Windows, macOS, and Linux. It offers a surprisingly comprehensive feature set for a free program. Its tools include filters, brushes, transformation tools, selection tools, and layer and masking capabilities. GIMP supports colour correction, cropping, resizing, retouching with clone and healing tools, and even scripted automation through languages like Python and Perl.

It provides features including layers, layer masks, various adjustments, cloning and healing tools, painting tools, and filters – all for free. While it doesn’t match Photoshop’s speed or polish, GIMP is a capable alternative for students, beginners, and anyone who needs professional-level editing on a budget.

Other notable software 🔗

Beyond Photoshop and GIMP, several other applications serve different needs:

Adobe Lightroom is designed for batch photo management and non-destructive RAW processing. It’s popular among photographers who need to process large volumes of images efficiently. Affinity Photo is a one-time purchase alternative to Photoshop, offering professional-grade features like layer-based editing, RAW development, and HDR merging. Canva is a browser-based tool aimed at non-designers who need to create social media graphics and simple edits quickly. Pixlr and Fotor are online editors that offer quick, accessible tools for basic corrections without installing any software.

Essential image editing tools and techniques 🔗

Regardless of which software you use, there’s a core set of tools and techniques that form the foundation of image editing. Let’s go through them.

Cropping 🔗

Cropping is the removal of unwanted areas from the edges of an image. It is one of the most basic photo manipulation processes, used to remove distracting elements, change the aspect ratio, or improve overall composition. In photojournalism, cropping is considered one of the few permissible editing actions alongside tonal adjustments and sharpening.

Most editing software lets you crop using freeform selection or preset aspect ratios (such as 1:1 for Instagram, 16:9 for YouTube, or 4:3 for standard displays).

Resizing and scaling 🔗

Image editors can resize images in a process often called image scaling, making them larger or smaller. They use a mathematical process called resampling to calculate new pixel values. Reducing image size generally works well, but enlarging a raster image can lead to noticeable quality loss. Images destined for web use are typically kept smaller (around 1200-2000 pixels wide) to ensure fast loading times.

Colour correction and adjustment 🔗

Colour correction involves adjusting the brightness, contrast, saturation, hue, and white balance of an image. Many programs offer basic automatic enhancement features that correct colour hue and brightness imbalances with a single click. For more precise control, editors provide tools such as:

Levels and Curves – These allow you to adjust the tonal range of shadows, midtones, and highlights independently. Brightness/Contrast – A straightforward slider-based tool for global adjustments. Hue/Saturation – Lets you shift colours or increase/decrease their intensity. White Balance/Colour Temperature – Corrects colour casts caused by different lighting conditions.

Retouching tools 🔗

Retouching involves fixing imperfections in an image. The most commonly used retouching tools include the Clone Stamp (copies pixels from one area to another), the Healing Brush (blends sampled pixels with the surrounding area for seamless fixes), and the Red-Eye Removal tool. Some editors also support removing unwanted objects by using the clone tool to replicate surrounding textures over the distraction.

Selection tools 🔗

Selection tools let you isolate specific parts of an image for targeted editing. Common selection tools include the Rectangular/Elliptical Marquee, Lasso (freehand), Magic Wand (selects pixels of similar colour), and Pen Tool (creates precise paths around objects). Good selection skills are crucial for tasks like background removal and localised adjustments.

Layers and masks 🔗

Layers are one of the most powerful concepts in image editing. Layers allow you to apply effects or adjustments to specific areas of an image without affecting the rest. Masks let you hide parts of an image while preserving the original data. This enables non-destructive editing – you can always go back and modify or remove any change you’ve made. Professional workflows rely heavily on layers to manage complex compositions.

Filters and effects 🔗

Filters are pre-built adjustments you can apply to an image. Common filters include sharpening (to enhance detail), blurring (for background softening or privacy), noise reduction (to clean up grainy images), and artistic filters (for stylistic effects). GIMP’s version 3.0 introduced non-destructive filters, allowing users to apply effects without permanently altering the original image.

Digital image file formats explained 🔗

Choosing the right file format is just as important as the editing itself. Different formats serve different purposes depending on factors like image quality, file size, transparency support, and whether the image is for web or print use. Here are the formats you need to know.

JPEG (Joint Photographic Experts Group) 🔗

JPEG is a compressed digital image format that trades storage size for image quality. The compression method is typically lossy, meaning original information from the image is not retained and cannot be restored. Despite this, JPEG remains the most widely used image format globally. It is often the default setting on cameras, supports a full spectrum of colours, and almost all devices and programs can open and save it.

JPEG is best suited for photographs, web images, and social media. However, every time you re-save a JPEG, it compresses again and loses more quality – so it’s not ideal for images that require repeated editing.

TIFF (Tagged Image File Format) 🔗

TIFF files are common in publishing, photo editing, and graphic design. They are versatile and compatible with a range of operating systems and programs. TIFF supports lossless compression, meaning image quality is fully preserved regardless of how many times you save the file. This makes TIFF a great format for extensive post-processing, often producing the highest-definition images compared to other formats.

The trade-off is file size – TIFFs are significantly larger than JPEGs, which makes them impractical for web use or email sharing. They’re best used for archival storage, professional printing, and scanning.

RAW 🔗

RAW files are image files that are not processed at all and cannot be printed without being edited first. RAW is the preferred option for professional photographers because the camera doesn’t apply any permanent adjustments to the image data. This gives photographers maximum control over exposure, white balance, and colour grading during post-processing.

RAW isn’t a single format – it varies by camera manufacturer. RAW files may use formats such as NEF (Nikon), DNG (Adobe), or CRW (Canon). These files need to be processed through a RAW converter like Adobe Lightroom, Capture One, or Darktable before being exported to JPEG or TIFF for final use.

PNG (Portable Network Graphics) 🔗

PNG was originally developed as a non-patented replacement for GIF files. It uses lossless compression and supports partial and total transparency. This makes it excellent for web graphics, logos with transparent backgrounds, and images that need to be layered over other content.

There is compression involved but not as much as in GIFs, which allows PNG to retain high image quality. However, the size is still larger than a JPEG. PNG is not typically used for photographs on the web when file size is a concern – JPEG is usually preferred in those cases.

GIF (Graphics Interchange Format) 🔗

GIF is a format best known for supporting simple animations. It’s great for graphics and visuals with animation, and web designers often use it for simple logos and banners. However, GIF is limited to 256 colours, making it extremely lossy and unsuitable for photographs. Its primary use today is for animated content and simple web graphics.

Other formats worth knowing 🔗

WebP – Developed by Google, WebP provides both lossy and lossless compression with significantly smaller file sizes than JPEG and PNG. Lossy WebP images are on average 25-35% smaller than JPEG images at similar quality levels. It’s increasingly popular for web use. PSD – Adobe Photoshop’s native format that preserves layers, masks, and all editing data. Essential for ongoing design projects. SVG – A vector-based image format commonly used for logos, icons, and other scalable graphics on the web.

How to choose the right format 🔗

Selecting the appropriate file format depends on what you plan to do with the image:

For web and social media, JPEG works best for photographs and WebP for optimal compression. Use PNG when you need transparency. For professional printing, TIFF is the standard, offering lossless quality at high resolution. For photography workflows, always shoot in RAW if your camera supports it, process in software like Lightroom, and then export to JPEG or TIFF as needed. For logos and illustrations, use vector formats like SVG or AI to maintain scalability, and export to PNG or JPEG for web display.

The role of image editing in journalism and media 🔗

In journalism, image editing serves a very specific purpose: to improve technical quality without altering the truth of the photograph. Cropping, tonal balance, colour correction, and sharpening are generally considered the permissible editing actions in modern photojournalism. Manipulating an image to misrepresent reality – such as removing people, adding objects, or substantially altering colours – is considered a serious ethical violation in newsrooms around the world.

Understanding these editing fundamentals isn’t just a technical skill. It’s about knowing what’s possible, what’s acceptable, and how to present visual information honestly. As media professionals, the tools and formats you choose directly affect the quality and integrity of the stories you tell.

What do you think? With free tools like GIMP becoming increasingly powerful, do you think paid software like Photoshop still justifies its subscription cost for students and aspiring journalists? And where should the ethical line be drawn when it comes to editing photographs for news stories?

References

1. https://www.adobe.com/products/illustrator.html
2. https://www.adobe.com/products/photoshop.html
3. https://www.gimp.org/
4. https://www.darktable.org/