Hi: Lets try this: From within iPhoto, multiple select your photos. From the "File" menu select "Export". From within the export window you can customize numerous characteristics, including file size, and save location. Save the files to a folder on your desktop, right <ctrl> click on the folder and select "Compress Folder". You can now drag the folder on to the Mail icon in the dock and create your new email.
Hope this helps
Stedman