silvadori Hi. That will happen to very large images (>5000px) as a precaution to protect your server from resizing images that it may not be able to resize. See config options image_resize_max_pixels
:
https://www.files.gallery/docs/config/#image_resize_max_pixels
Try to increase it from 30000000
to a higher value:
'image_resize_max_pixels' => 99999999,
This will allow your server to resize larger images. It will probably work fine, but if you get an error, it means the images are larger than your server PHP memory is capable of.
If the above change fails, you could also try to increase the image_resize_memory_limit
from 128
to 256
.
https://www.files.gallery/docs/config/#image_resize_memory_limit
'image_resize_memory_limit' => 256, // number
Keep in mind, these options are in place as sensible limits to prevent your server from failing. It will probably work, but if you get new "broken images" in the layout instead, it's because the images are too large to resize on your server. Keep in mind, as in your screenshot, you have many 7000px+ images, it will take time and a lot of resources from your server to resize all these images.