Can JPG to PNG improve quality?
No. When a JPG is saved, some pixel information is already discarded, and no conversion can bring it back.
Converting JPG to PNG only stores it in a format that will not keep losing quality — blurry edges or compression noise will not become sharp again.
Why is the converted file larger?
PNG is a lossless format that keeps every pixel, while JPG already removed that redundancy through lossy compression.
So JPG to PNG usually produces a larger file. This is normal and not a problem with the tool.
Can JPG become transparent?
Not directly. JPG contains no transparency information; the original white (or any solid) background was saved as real pixels.
In the resulting PNG, those areas are still opaque. To get a transparent background, you need to cut out the subject manually with an image editor afterward.
When is converting to PNG worthwhile?
When you need to keep editing losslessly and save repeatedly (each JPG save loses more quality); when you need a transparency channel; and when the target platform only accepts PNG.
If you only want a smaller file, converting to PNG is a poor choice — use WebP or a compression tool instead.