Guides
The background knowledge behind the tools — what each format is actually for, why a file is the size it is, and which numbers matter when you print.
- JPG vs PNG vs WebP vs AVIF: which should you use? A plain comparison of the four formats that matter, what each is actually good at, and the three rules that cover almost every decision. Updated 19 September 2026
- How to reduce image file size without wrecking it Why images are large, the order of operations that actually works, and how to hit a specific file size like 100 KB without the picture falling apart. Updated 19 September 2026
- Image sizes for every social platform Current pixel dimensions, file size limits and formats for Instagram, YouTube, LinkedIn, X, Facebook, TikTok, Pinterest and the major marketplaces. Updated 2 November 2026
- What your photos reveal, and how to remove it EXIF records where and when a photo was taken, and on what. What is actually in there, who can see it, and how to strip it without degrading the image. Updated 19 September 2026
- DPI, PPI and print size, explained properly Why changing the DPI number does nothing to your image, what actually determines print quality, and how to work out whether a photo is big enough to print. Updated 1 October 2026
- HEIC photos: what they are and how to open them Why your iPhone saves HEIC instead of JPG, which devices can open it, how to convert it without losing quality, and how to stop it happening. Updated 1 October 2026
- Aspect ratios explained: crop, pad or stretch? What 4:3, 3:2, 16:9, 4:5 and 9:16 actually mean, which one each camera and platform uses, and the only three ways to change a photo from one to another. Updated 24 September 2026
- Favicon sizes: the files a website actually needs The short list of favicon files a modern site needs, the exact HTML to include them, and why most "complete favicon packages" are twenty files too many. Updated 24 September 2026
- Transparent images: why backgrounds turn white How transparency is stored in an image, which formats support it, why it disappears when you convert or upload, and how to fix the grey halo around cut-outs. Updated 6 October 2026
- How to resize an image without losing quality Why making an image smaller is safe and making it bigger is not, what resampling actually does, and the order of operations that keeps photos sharp. Updated 24 September 2026
- Scan documents with your phone into a clean PDF How to turn a phone photo of a page into a straight, readable, reasonably sized PDF, and how to get searchable text out of it. Updated 6 October 2026
- Passport photo at home that gets accepted The photo rules that cause most rejections, how to light and frame the shot with a phone, and how to size and print it for the US, UK, EU and Canada. Updated 30 October 2026
- Fix bad edges after background removal Halos, jagged outlines, lost hair and missing parts after removing a background: what causes each one and the fixes that work, from the photo to the final export. Updated 30 September 2026
- Hide info in screenshots: blur isn’t enough Which ways of hiding names, numbers and addresses in an image can be undone, which cannot, and a checklist for sharing screenshots and photos safely. Updated 30 September 2026
- Product photo rules for Amazon, Etsy, eBay and Shopify Main image sizes, backgrounds and rules on Amazon, Etsy, eBay and Shopify, the mistakes that get listings flagged, and how to shoot at home. Updated 30 September 2026
- App icon sizes for iOS, Android and the web The icon files an iPhone app, an Android app and a web app actually need, the safe areas each platform crops to, and the mistakes that get icons rejected. Updated 12 October 2026
- Colour-blind friendly charts, maps and designs How the common types of colour blindness change what people see, which colour pairs fail, and simple fixes that make a chart or design readable for everyone. Updated 12 October 2026
- Turn a photo into art: which style suits which photo Oil painting, watercolour, pop art, low poly, stained glass, duotone, sketch and tilt-shift: what each effect does, which photos suit it, and good settings. Updated 12 October 2026
- Cross-stitch and paint by numbers from your own photo How to choose a photo, how many colours and stitches to use, how big the finished piece will be, and how to print the chart or outline for a home-made kit. Updated 12 October 2026
- Sprite sheets and seamless textures for games What a sprite sheet and a texture atlas are, how to pack frames for Phaser, Unity or Godot, and how to make a texture that tiles without visible seams. Updated 12 October 2026