Wrong thumbnail shown after sending an image in 1.4.3

User sent an image in a plaintext room; the wrong thumbnail was shown. Everyone else saw the right thumbnail & zoomed image, but the sender saw an unrelated image. Might be cell recycling of some kind?

No file, test, or entry point is named. Start by reproducing the issue in a plaintext room on version 1.4.3 and compare the sender's thumbnail with the zoomed image and other users' views. Done means the sender consistently sees the correct image thumbnail and zoomed image.

Written by the indexing model from the issue text.