Inspect an image's channels
A noisy JPEG often hides the noise in one channel. Split R, G, B, and alpha into grayscale views to find it.
Tools used in this guide
The job
JPEG artifacts cluster in blue, sensor noise splits unevenly, and alpha edges carry their own story. Viewing each channel as grayscale exposes what the composite hides.
Four grayscale views
Choose an image and the tool produces R, G, B, and alpha channels — bright means that channel is strong there. Each downloads as its own PNG.
Worked example
A noisy product photo: the R and G channels look smooth while B shows blocky JPEG noise — typical, since blue gets the least bits. The alpha channel of a PNG logo shows the matte line as a mid-grey halo along the edge.
Scope
PNG/JPG/WebP up to 25 MiB and 40 MP. JPEG input has no alpha, so its alpha channel comes back solid white. Channels are views, not a channel mixer — recombine them in an editor.