a size issue.
Many ISP email servers will baulk at large size attachments.
The size of image files in KBytes could be significant, depending what file format they are in.
For example, an image, (photo), which has a .bmp file extension is considerably larger than the same image file with a .jpg file extension.
I have just tested one of mine. A JPG image sized 1.11 MB, (1167.7 KB), jumps to a whopping 7.50 MB, (7864.0 B), when I convert it to BMP.
So have a look at your pictures folder and see what file sizes they are and what file format they are.
My Windows Live Mail program will not send my photo email attachments. I get error messages, emails dumped into the outbox, and other crazy stuff. Either as attachments or using their photo album. Any thoughts on how to fix this, what may be causing it? It suggests I delete the email and try again or split it up, neither of which is helpful (I can't even send one pic, hard to split up just one!).