A 100 KB target is preset. Drop your images in and each one is shrunk until it fits.
It searches for the highest quality between your setting and 40 that lands under 100 KB. If even quality 40 is too big, it scales the image down a little and searches again. A '✓' in the list means it made it.
PNG has no quality setting, so with a size target it is saved as JPG; transparent areas turn white.
This page is the Compress Images tool with settings prepared for this task. Nothing you add is uploaded.
No. Shrinking and saving happen in your browser. Load the page, go offline, and it still works.
A phone photo of 3–5 MB usually lands at 300–600 KB at 2000px and quality 78. Already-small files barely change; if one gets larger (+%), keep the original.
Below about 70, gradients and edges around text start to smear. Use 75–82 for screens and 90+ for print.