Conversion sounds trivial and quietly loses things: transparency disappears when you convert to JPG, quality stacks up damage when you re-encode an already-lossy file, and vector sharpness vanishes the moment an SVG is rasterized at the wrong size.

These guides cover each common conversion path and what to watch for in that specific direction — the iPhone HEIC problem, getting crisp PNGs out of SVGs, turning GIFs into something modern, extracting images from PDFs, and dealing with camera RAW. The recurring rule across all of them: convert from the original whenever possible, because every re-encode of an already-compressed file compounds the loss.