Why convert PNG to JPG
PNG stores an image losslessly, which means every pixel is preserved exactly and the file is large — a full-screen screenshot can easily exceed 2 MB. For a photograph, that precision buys almost nothing your eye can detect, and JPEG will store the same picture in a small fraction of the space. This is the right conversion when a form has a size limit, when you are attaching photographs to an email, or when a page full of PNGs is loading slowly.
What this conversion costs you
- Transparency is flattened. PNG's alpha channel has no equivalent in JPEG, so transparent areas become white. This is the single most common surprise in this conversion, and it is why logos should stay as PNG.
- Sharp edges pick up artifacts. JPEG was designed for photographs and handles smooth gradients well. Hard black-on-white edges — text, screenshots of interfaces, line drawings, charts — develop faint smudging around them, which is visible if you look closely.
When not to do this
Keep PNG for logos, icons, screenshots containing text, diagrams and anything with transparency. The size saving is real, but text that turns fuzzy is a bad trade for a screenshot whose entire purpose is legibility.
Common questions
Why is my PNG screenshot so large?
PNG is lossless, so it stores every pixel exactly instead of approximating. That is ideal for accuracy and expensive in bytes, especially for full-screen captures.
Will my transparent background survive?
No. JPEG has no alpha channel, so transparent areas are filled with white. Convert to WebP instead if you need both a smaller file and transparency.
Is PNG or JPG better for a photograph?
JPG, almost always. Photographs have no hard edges and no transparency, which is exactly the case JPEG was designed for, and the file will be a fraction of the size at indistinguishable quality.