Why 100KB is a comfortable middle-ground target
Where 20KB and 50KB limits usually come from legacy government and exam-board systems, a 100KB cap tends to show up on platforms built more recently — marketplace listings, portfolio sites, and job boards that want to keep average storage costs predictable without forcing users into visibly degraded photos. It’s tight enough to matter for a full-resolution phone photo (which can easily be 3-5MB), but loose enough that the result usually looks clean at normal viewing sizes.
How the search finds the best quality automatically
The tool runs a binary search over JPEG quality: encode at a mid-range setting, check the actual output byte size, then move the quality up or down and repeat, converging on the highest setting that still fits at or under 100KB. Because 100KB is a relatively generous budget, the search typically lands at a noticeably higher quality percentage than tighter targets like 20KB, which is why images compressed to 100KB usually show fewer visible artifacts even under close inspection.
When resizing still helps
At 100KB, most reasonably-sized photos compress cleanly without any extra steps. The exception is very high-resolution source images — a modern phone can easily produce 12-48 megapixel photos, and squeezing that much detail into 100KB still means discarding a lot of information relative to what a smaller image would need. If you’re not seeing the sharpness you expect, resizing down to whatever the destination actually displays (rarely more than 1500-2000px for a web listing photo) before compressing will use the same byte budget far more effectively.
Batch workflows
Because 100KB is common across many photos in a single upload session — a full listing gallery, a batch of portfolio images — this tool supports dropping in multiple files at once, each compressed independently to the same target, so you can prepare an entire set in one pass rather than repeating the process file by file.