An aside about image formats. When you factor file size into the equation, essential for web work, a format such as GIF or PNG is better for capturing screenshots of menus, dialogs and linework. JPEG is better for high-color images.
Typically, I capture screenshots with 5-bit (32 color) adaptive palette GIFs, to achieve remarkably small size and yet still high clarity. For larger images, 8-bit PNG frequently competes or beats GIF.
A JPEG of the same image would be substantially larger to achieve the same quality. It's just a function of how each compression method works and the color palette used.
On the other hand, if the capture includes part of a photo or render, then JPEG is the only way to go (speaking purely about file size/quality trade-off where file-size is the emphasis), because a larger color palette is needed and there are very few large blocks of a single color (the trick behind GIF compression).
Lots of people viewing screenshots here, or general web pages, are still using dial-up and so keeping file sizes down by appropriate choices helps them out.
That said, I've used SnagIt (Windows) since version 6.0 and find it incredibly flexible and customizable, with quick annotation right within SnagIt itself. My only complaint is that it cannot seem to remember where you last saved a file, and so you have to navigate every time to the save folder. (Was not a problem with v 6.0)
I'm trying the Ambrosia's SnapzPro X 30 day demo on Mac OS X and find it quite limited in comparison to SnagIt. In particular, it is incapable of producing adaptive, reduced palettes (such as 5-bit GIF or adaptive 256 color PNG) ... the smallest palettes it will use are standard Mac or Windows 256 color (web color) palettes ... which result in poor images and large file sizes. The only option is to capture at high-color, and edit in Photoshop. Too time-consuming.
SnapzPro constrains the names and locations of saved files as well.
On the other hand, a feature that SnapzPro has that SnagIt lacks is real-time image preview just like the Photoshop save-to-web feature. If you are saving a JPEG, you can see the preview quality to determine the desired compression setting. SnagIt doesn't offer this ... just a blind setting of a quality level.
Lacking a better Mac screenshot tool, I suppose I'll still take most of my screenshots from Windows with SnagIt...
PS Just tried 'Capture Me'. Thanks for the link, Dave. It does suport adaptive 256 color palette for PNG and the price is right. However, you can't capture dynamic things, though, such as cascading menus, pop-up menus, mouse cursors, etc as far as I can tell.
One of the forum moderators • AC 26 USA and earlier • macOS Ventura 13.2.1, iMac Pro 10-Core, Radeon Pro Vega 64