How to Make an Image Background Transparent Online
PNG can store an alpha channel, the extra value per pixel that says how see-through it is. JPG cannot; the format has no slot for it at all. That's why exporting a "transparent" cutout as JPG hands you back a flat coloured rectangle where the background used to be, whichever settings you picked around it. See Change a Photo Background to White for more on that failure mode. Here, the short version is enough: pick PNG or WEBP, not JPG, whenever you actually need to see through the background.
Reading the checkerboard
After ZeroBG removes a background, the preview shows a checkerboard pattern behind your subject. It follows whichever theme your browser is in, light or dark, so the exact colours will differ depending on your setup; what matters is that the pattern itself is not part of your image. It's the standard convention editors like Photoshop and GIMP use for "nothing is here", because a plain preview square would be indistinguishable from an actual solid-colour background. Where you can see the checkerboard through part of your subject, that area is transparent or partially transparent in the real file. It's a preview-only stand-in and disappears once the image sits on top of something else, a web page, a slide, another photo.
Choosing PNG or WEBP
PNG is the safer default: universally supported, lossless, the format most tools expect when you say "transparent image". WEBP with alpha typically produces a noticeably smaller file at similar visual quality, useful if you're loading several cutouts on a page and care about load time. The tradeoff is that some older tools, a handful of email clients, and some print or design software still expect PNG specifically rather than WEBP. For a logo on a site you control, WEBP is a reasonable pick. For a file you're handing to someone else, PNG is the safer bet unless you already know their tools handle WEBP. ZeroBG's export panel gives you a quality slider for WEBP (and for JPG where it applies); for PNG there's nothing to tune, since PNG compression doesn't discard pixel data. If you're not sure which the destination supports, PNG is the one that never surprises anyone; treat WEBP as an optimisation you reach for once you already know the target accepts it.
When the cutout isn't clean
The segmentation is good but not perfect, and the two places it most often struggles are hard edges and hair. On a fairly sharp edge, the side of a mug, a phone case, you may see a thin halo of the old background colour clinging to the outline, more visible against a new background of a very different colour. How wide that halo looks depends on your image's resolution and how much the mask feathers at that edge, so there's no fixed size to expect; check it rather than assume it. On hair or anything with fine wispy detail, the model decides pixel by pixel how transparent each strand should be, and it sometimes gets this wrong visibly: a clump of hair rendered fully solid when it should fade out, or background bleeding into what should have stayed solid.
ZeroBG's manual touch-up brush is built for exactly this. Switch to it after the automatic removal finishes. There's one adjustable brush size, shared by both modes:
- Erase paints transparency onto areas the model left opaque by mistake, a halo fragment, a stray patch of background.
- Restore paints opacity back onto areas the model wrongly erased, a clump of hair, a shadow you actually wanted to keep.
If a touch-up session goes wrong, the reset button discards your manual edits and restores the original AI result, so you can redo the touch-up pass without rerunning the background removal itself. For genuinely hard hair, flyaway strands against a busy background, the quantised model ZeroBG uses to keep the download small may still leave a cleaner job to a paid cloud service tuned specifically for hair matting. The touch-up brush closes most of that gap by hand, but won't make an impossible-to-segment wisp perfect. Touching up in several short passes works fine: correcting one small area doesn't affect anything else in the cutout, so there's no need to fix everything in a single sweep before you check the result.
Checking your result properly
Three tools in the editor are built for judging a cutout rather than just producing one, and they're worth using before you export anything.
- The before/after comparison slider. Drag it to compare the original image against the cutout directly, rather than relying on memory of what the edge used to look like. This is the fastest way to spot a halo you'd otherwise miss.
- The 17 preset backdrops. A halo or fringe that's invisible against one backdrop colour can be obvious against another. Cycle through a few of the preset backdrops, a light one, a dark one, a busy photo, before deciding the edge is clean. This matters more than picking a single "neutral" test colour, because the backdrop you'll actually use might not be neutral at all.
- Aspect-ratio presets for the output canvas. If the transparent image is going somewhere with a fixed frame, an app icon slot, a banner, a specific card size, set the ratio before you export rather than cropping afterwards. Cropping after the fact can cut into a subject that was correctly positioned for the original canvas.
Once you've checked the edge against a couple of backdrops and the aspect ratio matches where the image is going, export. Open the exported file itself, not just the ZeroBG preview, in whatever viewer or app you'll actually use it in, and confirm it looks transparent there too, not only against the editor's checkerboard.