The tell is not six fingers
You can spot a raw generation across a room, and it is rarely because of an anatomical error. It is because of five specific, fixable things — and fixing them takes about ten minutes in a free editor.
What is actually wrong with a raw generation
The tone curve is mushy. Generated images tend to sit in the midtones with weak blacks and no clean white. Open Curves, pull the bottom-left point right until the darkest shadow is genuinely black, and pull the top-right point left until something in the frame is genuinely white. Then put a gentle S in the middle. Twenty seconds, and it is the single largest improvement available.
Not Brightness/Contrast — that shifts everything uniformly and crushes both ends. Curves, because you are choosing which tones move.
Everything is equally sharp. A real lens is sharp at the focal plane and falls off. A generated image is often uniformly crisp from foreground to horizon, which the eye reads as artificial without knowing why. Select the far background, add a small Gaussian blur — one or two pixels at 1024 wide — and the frame acquires depth.
There is no grain. Every photograph ever taken has sensor noise or film grain. Generated images have none, and the absence is conspicuous. Add a fine, uniform monochrome noise across the whole image at low opacity. This is the cheapest single move that makes an image read as photographic.
The colour is model colour. Every model has a cast. Put two generations side by side and they will not match, which is why a set of six looks like a stock-photo bundle rather than a campaign. Pick one image as the reference, then colour-balance the other five to it — usually a small shift in the shadows and highlights, per image.
Inpainted regions have soft seams. A pass with the clone or heal tool along the boundary, at low opacity.
Text: always replace it
If there is a word in your image, replace it with real type. Always, even from a model that renders text well.
Three reasons. Generated letterforms are subtly wrong at large size — spacing that no typeface would use, an inconsistent stroke weight on one letter. The text is not editable, so a client's copy change means regenerating the whole image. And the kerning and alignment are the parts a designer is paid for. Set the type in Photopea, GIMP, Inkscape or Canva over the generated plate. Design foundations covers how to set it well.
The free stack, and the phone
Photopea runs in a browser, opens and saves PSD files, has Curves, layers, masks and healing, and costs nothing. It is the answer for anyone on a Chromebook, a school computer or a machine that cannot install software. It works in a phone browser too, though it is a fight.
GIMP and Krita are free desktop applications; Krita is more comfortable for painting and masking, GIMP for general retouching. darktable and RawTherapee do the tone and colour pass better than either.
On a phone: Snapseed has a proper curves tool and a grain control, both free. That is genuinely enough for the tone, colour and grain pass described above. Do it on the phone, and the image will already be ahead of most raw output.
The full technique for all of this is image editing. This lesson is about knowing that you have to.
Work non-destructively, because the note is coming
Keep the generation on its own layer. Do the tone pass as an adjustment layer above it, the grain as a separate layer, the type as live text. Export flattened, keep the layered file.
The client will ask for one change. If you baked everything into the pixels, one change is a regeneration. If you worked in layers, it is a click.
Name your files with something you will understand in six months, deliver flattened PNG or JPEG at the size actually needed, and keep the working file and the original generation, seed included.
Today: take your best generated image, open Photopea, apply Curves and add fine grain. Put the before and after side by side. Ten minutes.
Before you move on