我遇到过类似的问题。它与.png的保存方式有关。

I had similar problems. It has something to do with the way the .png is saved.

尝试通过 https://tinypng.com/传递文件一>。它已经为我工作了好几次。

Try passing the file through https://tinypng.com/. It has worked for me several times.