Why tiny JPEGs look different in Chrome

That tiny JPEG icon looking chunkier in Chrome isn't a rendering bug—it's a clever memory shortcut.

Developer Guillaume noticed a 15-pixel JPEG logo rendered noticeably thicker in Chrome than in Firefox. The culprit: Chrome's image library uses a optimization called partial IDCT scaling. Instead of uncompressing a full JPEG into memory and shrinking it, Chrome decodes only the low-frequency color data needed for small sizes.

Why it matters: Fully uncompressing a large JPEG to display a tiny thumbnail can waste megabytes of memory for a result that needs only kilobytes. Chrome's shortcut saves RAM and processing time. The trade-off: skipping high-frequency details removes soft edge gradients, making small icons look extra bold.

Know this: Don't use JPEGs for icons—use SVGs instead. JPEGs were built for photographs, where losing high-frequency detail doesn't ruin the image shape.

Next time a logo looks like it gained weight in Chrome, blame the trick saving your RAM.