A JPEG loses a little quality every single time it's opened, edited, and saved again as a JPEG, since its compression is lossy and each re-save recompresses the image from what's already a slightly degraded version, a kind of generational loss that quietly compounds over several rounds of editing. This tool converts a JPEG into PNG, a lossless format, so any further edits and saves after the conversion stop losing quality altogether rather than degrading further with each pass. Useful for converting a JPEG to PNG before a round of edits so repeated saving afterward doesn't degrade it further, preserving a photo's current quality exactly instead of letting one more JPEG re-save erode it, or converting an image into a format where saving it five more times looks identical to saving it once.