Alpha Channel
Also called alpha transparency, transparent background, cutout png
An alpha channel is an extra layer in an image file that records how transparent each pixel is, alongside the red, green, and blue colour data. It is what allows a cutout PNG to sit on any background colour without a white box around it.
In other words, it is the part of the file that says which pixels are the product and which are nothing at all, so the background can be dropped.
How transparency is stored
A normal image holds three values per pixel: red, green, blue. Add an alpha channel and there is a fourth, running from fully transparent to fully opaque, with every step in between.
Those in-between values matter more than the extremes. A prong edge that half covers a pixel gets a half-transparent value, which is what keeps a cutout looking clean rather than crunchy at the outline.
PNG and TIFF support alpha. JPEG does not, which is why a JPEG always arrives with a solid background baked in.
Why sellers ask for it
A cutout image drops onto any background. The same render works on a white product page, a coloured seasonal banner, an email header, and a marketplace listing, without a grey halo giving it away.
It also makes compositing easy. Layer the piece over a lifestyle photo, place it in a collection grid, or paste it onto a hand shot, all without cutting anything out by hand.
Standard delivery here is on a white background, sized for ecommerce, which is what most storefronts and marketplaces expect. If your layouts need cutouts on transparency, ask when you send the file.
Questions about Alpha Channel
Can I get renders with a transparent background?
Standard delivery is on a white background, ecommerce ready. If you need transparent PNGs for banners or compositing, mention it when you send your file.
Why does my JPEG have a white box around the product?
JPEG has no alpha channel, so it cannot store transparency. Save as PNG or TIFF if you need a cutout.