permissions important for image module to work

By default the ./files/images and ./files/images/temp directories are given 740 permissions. Then the images seem to be there and everything but do not appear!!!
at the starting line
at the starting line

When the dirs are given 755 permissions... ... it works! Now, what about thumbnails?

By default the ./files/images and ./files/images/temp directories are given 740 permissions.
Then the images seem to be there and everything but do not appear!!!

at the starting line

at the starting line

When the dirs are given 755 permissions…
… it works! Now, what about thumbnails?

 06-0306-03