Flarum supports markdown to add image, but if a image's name contains '300x250' characters, we will not see the image in the post.
For example,
1
![](https://f004.backblazeb2.com/file/stone233/300x150.jpg)
2
![](https://f004.backblazeb2.com/file/stone233/300x250.jpg)
1
2
Only the first image can be seen, but they are the same image, just with a different name.