In the AOL for Mac OS X application, if you
drag a group of photos into the attachment
area, they are automatically zipped ...
This is true for any group of files, not just image files. The application lets you optionally compress a single file or send it as is, but if the file count is greater than one, all files will automatically be compressed into a single one for sending. A preference setting ("AOL" menu -> "Preferences..." -> "Mail") lets you choose between zip & sit (Stuffit) compression formats. In the same preference pane, you will find other mail-related options, like saving sent or received email, notifying you before opening received files containing images, & so on.
A separate preference pane, "Downloads," controls received file behavior, including automatically uncompressing received files, deleting the compressed version after extracting its contents, etc.
... which I consider an advantage.
The application has its strong points & its weak ones. Because it hasn't been updated for several years, it doesn't take advantage of some features of Tiger, notably Spotlight searches. The built-in browser is an older version of Internet Explorer, which isn't compatible with many web pages, so if you click on links in email, you are likely to have problems. The work around is to copy the links & open them with another browser, but this is somewhat clumsy.
Worse, selecting the "Helpers" preference pane (used to set built-in browser options for handling web page content) hangs the application because this method is obsolete, & you must force quit the application to recover.
The app also doesn't give you access to some of your AOL account's mailboxes, most notably the "Spam" one. Since AOL puts messages it considers spam in this mailbox, on occasion a legitimate email may end up there, so it is worth checking it. Mail.app allows this, as does the web mail interface, but it is a sorely missed feature of the AOL OS X client.
I don't see any way to set that up with Apple Mail.
I don't either, short of using Automator and/or AppleScripts to build your own 'zipper-attacher.' I haven't actually tried this, but it looks feasible, if less elegant than the drag & drop method I suspect you would prefer.
Still, overall I find Mail.app to have enough advantages over the AOL app that manually zipping files for sending isn't enough of a drawback to make me want to use the AOL app anymore. However, you might find it best to use the AOL software to send zipped files & Mail.app for everything else.