File Manager picture problems
What's the resolution of these pics?
Is the site available somewhere we can try this out? Or maybe you can post screenshots?
You need to make sure this directory and all of the directories inside of it have their permissions set to writable.
Once you do that, you can select the images you have already uploaded to the file manager and from the drop menu select "Rescan".
This will generate a thumbnail of the image instead of the default "flower icon".
Your uploads from that point forward will create thumbnails as normal.