|Some email servers have software that filters out files with certain file extensions because they may be malware.|
If you change the file extension to something the software won't filter out, the attachments will go through.
E.g. If you make an *.zip archive file with WinZip or similar that has all the .jpg files you want to send to that person in it who has that problem and attach that to the email, the *.zip file will probably go through, and that person will be able to look at the files in the archive because Vista has the built in ability to open and extract files from *.zip files .
All you need to do in Vista is select all the *.jpg files you want to send (e.g.hold down the Ctrl key and click on each one, slowly), RIGHT click - Send to - Compressed (zipped) folder, and it will make a *.zip file folder, randomly using a name of one of the files.
Rename the folder name if you like.
Attach that folder (zip archive file) to the email.