Due to the CSAM attack from some days ago, several lemmy admin decided to wipe all images from the attack period and others also prevented uploading until further notice (https://lemmy.world/post/4018526 for some info)
I had almost half of my image posts removed due to this and reuploaded them.
thanks a lot for info. i updated mine posts too. btw you can start editing post and save it right after. image will reappear. (tested on sdfeu instance)
You could do this because the initial image was still hosted on sdfeu and only the local thumbnail from LW was removed, but my affected posts were initially uploaded on LW and both the thumbnail and full image disappeared, hence the need to rehost.