After you select all the files and folders you want to include in the zip file, right-click or Control-click on any one of the items and select Compress from the pop-up menu. Shift-click to select a range of files or command-click to select nonadjacent items. Popular mail files on Mac OS including EML, EMLX, Images can be Read using this DMG Viewer utility. This tool supports to view DMG File of both Read-Only & Compressed Type.
Firefox 3 requires Mac OS X 10.4 or above.
Another option is TenFourMac, which is based on Mozilla 2.0 and Firefox 4 code. Mac OS X 10.4 users, and 10.5 users with a PPC Mac, can download the latest Firefox 3.6.xx release version for Mac OS, currently available from here or from the Mozilla CDN site (Firefox 3.6 requires Mac OS X 10.4 or above).