The quick test: place it on a colored background
Whether a PNG has real transparency is fastest to see by placing it on a colored or patterned background — the white default background of many programs won't reveal it: a white "hole" is invisible on white. How to test:
- Place the image on a colored layer in an image editor.
- Or drop it onto a colored web page/area.
- If the area around the subject stays see-through (the color shows through) → transparency present.
- If a white/colored box appears → no transparency.
An info or metadata tool often additionally shows whether an alpha channel is present — the image info tool reads the image characteristics browser-local.
Why the transparency disappeared
If the test gives a "white box," there's usually a clear cause:
- Saving as JPG in between. The classic: the image ran through JPG (which can't do transparency) at some point and was turned back into PNG afterward — the transparency had already been replaced by white. Why JPG does this is explained in The alpha channel and transparency.
- Export without an alpha channel. Some programs export PNG with a white background by default when the option isn't set.
- Background filled with white. An edit painted over the transparent area with white.
Can it be rescued?
Only partly — and that's the honest news. If the background has been replaced by a fixed color, the subject must be cut out again; the original, clean transparency is lost.
- Solid background (e.g. pure white) → often removes well again.
- Soft edges (hair, shadows) → a light fringe, the "halo," easily remains when cutting out anew.
The cut-out methods are in Make a background white (for transparency, then cut out against transparent instead of white). But the best route is always to find the real original with intact transparency.
So it doesn't happen again
The golden rule for images with transparency: never save as JPG in between. Transparency survives only in PNG, WebP, or SVG. If you edit a logo, stay in a transparency-capable format throughout — otherwise the alpha channel is irretrievably gone at the first JPG detour.
In short
- Test on a colored background — white hides a white hole.
- Usual culprit: a JPG detour replaced transparency with white.
- Recovery means re-cutting — the original alpha is gone.
- Never save transparent images as JPG.