What FitKB does Upload forms often reject photos for two reasons: the file is an iPhone HEIC image the site does not understand, or the file is larger than the limit (for example "maximum 50 KB"). FitKB fixes both in one step. Drop in a HEIC, HEIF, JPG, PNG or WebP file, choose a target such as 50 KB or 100 KB, and FitKB produces a standard JPEG that is at or under that size.
How the exact-KB engine works FitKB re-encodes your photo as a JPEG and runs a binary search over JPEG quality to find the highest quality that still fits your limit. If even low quality is too large, it reduces the pixel dimensions step by step and searches again, so a 5 MB phone photo can still reach 20 KB. To keep you safe with both ways portals count kilobytes (1,000 or 1,024 bytes), FitKB aims about 2% below the decimal limit: a 50 KB target produces a file of at most 49,000 bytes.
Range mode for strict portals Some exam and government portals require a minimum as well as a maximum, such as 20–50 KB. Choose "Between min and max KB" and FitKB keeps the result inside both limits, enlarging the image slightly if the original is too small.
Check the result before you upload Each result shows the before and after size in KB and bytes, the pixel dimensions, and a side-by-side preview with a 1:1 zoom so you can judge sharpness. FitKB also checks the output file and confirms that EXIF metadata, including GPS location, has been removed.
Free and paid Two single-file exports per browser are free. FitKB Unlimited ($3.99 one-time) adds batch processing, portal presets and an offline HTML version you keep.
Privacy, in plain terms: FitKB runs entirely in your browser tab. Your photo is decoded and re-encoded on your own device using the browser canvas. Nothing is uploaded, there are no analytics or tracking scripts, and the page's Content-Security-Policy blocks connections to other servers. You can switch off Wi-Fi after the page loads and it keeps working.