Do you mean save for looking at later? Or download images?
Jerboa and Liftoff both let you save posts/comments, Jerboa definitely lets you download images, I haven't tried in Liftoff, but probably. Liftoff lets you download images too, just checked.
It is actually on the play store, but it's not the first result that comes up if you just search for liftoff. Search for 'liftoff lemmy' instead. I found it just yesterday, and have been trying it out after using Jerboa for a while, but getting a little annoyed at J's current bugs. So far I quite like Liftoff.
Ive found the page but saw, that the testflight is full. So I thought, I cannot join ( use the app in this phase) anymore. But since Ive switched to iOS recently and not be a pro on it, maybe Im wrong.
Ive already heard from it but I havent any idea how to install it. I found the github page, but their is no installation guide. And if I check the app store, I cannot find it. Maybe it coused by the fact, that the app is still in a beta phase, but I think it is a closed beta where I cannot join anymore. Am I wrong?