MATE 1.28 is technically "stable" being a release version. Debian/Ubuntu hasn't been able to update the package due to some packaging breakages on their side.
So the Porteus distribution is based on Slackware, and it's designed to be portable, OK. Could you help us replicate the issue?
- Were the GIFs animated on your system? (Here, in Caja 1.28 on Arch Linux, the previews are static, can't tell from your topic title)
- Are there any Caja extensions installed?
- How many files are in the folder?
- What kind of medium is this folder stored on? (e.g. HDD, USB 2.0 Flash Drive, remote SMB)
If it's a portable OS and on a USB flash drive, I'm willing to bet it's an I/O bottleneck. Trying to preview 100+ files when USB flash struggles to load more then 1-2 at a time is going to bottleneck the whole filesystem.
Otherwise, it might be a feature request to ask for disabling previews for specific media types on Caja's repository: