How to Convert Between Image Formats Without Losing Quality
Guide · Image Tools
Not all format conversions are created equal. Converting PNG to PNG, or making any change that doesn't touch a lossy-compressed format, doesn't lose anything. But converting to JPG — or worse, JPG to JPG to JPG across multiple edits — throws away a little bit of information every single time, and that damage compounds. Knowing which conversions are "free" and which cost you something changes how you should structure your workflow.
Lossless-to-lossless is always safe
PNG, WebP (in lossless mode), and most vector formats can be converted between each other, resized, or re-exported repeatedly without accumulating quality loss, because nothing is being approximated or thrown away at each step. If your design work happens across multiple tools and multiple save steps, keeping the working file in a lossless format until the very last export protects you from death by a thousand small compressions.
Every JPG re-save loses a little more
Each time a JPG is opened, edited, and re-saved as JPG, the compression algorithm runs again on data that's already been compressed once, which introduces new artifacts on top of the old ones. A photo that's been through five rounds of "open, tweak, save as JPG" looks visibly worse than the same edits made once on the original and exported to JPG a single time at the end.
The right order of operations
Keep a lossless master file (PNG or your camera's original) for as long as you're still editing, and only convert to JPG (or another lossy format) as the final step before publishing or uploading. If you need to make another edit later, go back to the lossless master and re-export — don't re-edit the already-compressed JPG copy.
When you genuinely have no master file
If all you have is an old, already-compressed JPG and you need to convert or resize it, there's no way to recover detail that's already gone — but you can at least avoid making it worse by doing all your remaining edits in one pass and exporting once, rather than saving as JPG at every intermediate step.