Attaching Photos to Email
What are the filesizes of your photos?
I would not recommend email attachments exceeding 10-20MB. This might mean only 3 or 4 photos per mail.
Also, if your photos are in jpg form then they are already heavily compressed and zipping them will not help.
There are better ways to share photos than emailing them (Dropbox, Google Drive, iCloud etc.)
If you must email photos I would open them in an editor and save copies at a lower resolution. Some mailing programs will do this automatically for you. You should get filesizes in the 500k to 1MB per picture.
HTH