When choosing wallpaper for low vision, the first question is not whether it looks minimal. Ask which actions must succeed at a glance. Common answers are reading the time, finding a frequently used app, and recognizing whether an alert matters. Write those actions down, then judge whether the background helps. Solid black, gradients, and beast imagery are only possible means.
Contrast must be tested at the weakest local point. A pale clock crossing a gold highlight or a dark icon sitting over ink-black pattern can lose its outline. W3C's warning about image backgrounds applies well here: inspect the small patch where the foreground actually lands instead of deciding that the whole picture looks dark enough.
Some people use visual landmarks to remember location: a stable block of color at the lower left, a clear central silhouette, or a distinct background for each Focus mode. Deleting everything can remove orientation. Keep landmarks few, fixed, and clearly different in shape, and never make an essential instruction available only through seeing the image.
Acceptance belongs in the user's own settings. Larger and bold text, display zoom, color filters, light and dark appearance can all change the overlay. Ask the person to complete the three actions and describe where effort remains. That evidence is more reliable than a designer declaring the screen clear from across the room. A good accessible wallpaper removes one extra moment of uncertainty.