I design book covers for a living, and on a mystery series where about 70% of sales are on Amazon, the 120x180px thumbnail is the real battleground. Pushing title contrast, one clear focal object, and stripping noisy textures bumped one A/B in Figma +0.6% CTR last week. What tiny visual tweaks have moved your clicks or sales?
I’ve gotten small lifts by adding micro-contrast for tiny sizes: a 1–2px inner shadow under the title and a subtle local-contrast pass on the focal object, then exporting with bicubic sharper. My quick test is “shrink to 80px and blur 2px — if it still reads, ship,” and I also mock it on both white and dark backdrops since Kindle surfaces vary. Have you tried a faint color halo (5–10% saturation) instead of black/white strokes to keep it from looking outlined?