That's more of an issue of your system. You need to install libjack and a graphics driver (e.g., mesa).

Mesa is installed by default. My GPU is an AMD, with the Caicos driver. I haven't installed mesa-utils, although I'm not sure if it will work—I had already installed the dependencies.

You need to install certain dependencies to run (at least) these AppImages; I haven't tried it with design software yet.
sudo apt install libfuse2 libopengl0 libjack0

My question is, will I have to do this for every app?
Isn't there a way to automate this?

@alexb3d no, you will not need to do this for every AppImage. The problem is AppImage is based on FUSE2 and the ecosystem has moved onto FUSE3 but AppImage is still on the old version so every AppImage needs FUSE2 to be installed. Most distros are getting rid of FUSE2 because it is no longer maintained by anyone. I don't know why AppImages still depend on it after years of this. OMG Ubuntu wrote an article about this a few years ago if you want to learn more. https://www.omgubuntu.co.uk/2023/04/appimages-libfuse2-ubuntu-23-04

I have a fresh installation of Ubuntu 26.04. FUSE2 (ie. fuse, fuse2, libfuse2t64 etc.) are non-existent on this version. Therefore, there is no way to run many AppImages on Ubuntu 26.04 out of the box. Is there a solution for the end users to run Fuse2-dependent AppImages somehow?

An AppImage is supposed to be distro-agnostic but when it fails to run on one of the top 10 distributions out of the box, users may think otherwise, in my humble opinion.

I used to evangelise for Autopackage, by the way, so my interest in standalone apps goes a long way back. :)

Dockers look cool for keeping your systems tidy. Better than compiling appimagetool for every distro you're planning for deployment. You might do that anyway but at least your system doesn't get destroyed.

Searching for information about AppImage online is one of the most frustrating experiences I've had with Linux. There are hundreds of everything. Even simple tasks like installing/integrate and updating are a real challenge. Not to mention creating an AppImage.

Could Anylinux-AppImages be a solution? It claims to require no dependencies and to update automatically.

I think that if AppImage wants to become an alternative for installing programs on Linux, it should be able to integrate with the desktop and update itself, because that has been one of its most important features. And obviously, it's in the software center.

None of them worked, so I installed Fuse and JRommanager worked. These ones don't, and I haven't tried any others yet. I understand that I'm missing libjack.so.0 and libOpenGL.so.0.

My question is, is this going to be the case forever? Is there a way to install these dependencies, or for them to install automatically?

lex@home:~$ '/home/lex/.apps/games/RetroArch-Nightly/RetroArch-Linux-x86_64/RetroArch-Linux-x86_64.AppImage' 
Setting $HOME to /home/lex/.apps/games/RetroArch-Nightly/RetroArch-Linux-x86_64/RetroArch-Linux-x86_64.AppImage.home
/tmp/.mount_RetroAFCmjmb/AppRun.wrapped: error while loading shared libraries: libjack.so.0: cannot open shared object file: No such file or directory
lex@home:~$ '/home/lex/.apps/games/pcsx2/pcsx2-v2.6.3-linux-appimage-x64-Qt.AppImage' 
Setting $HOME to /home/lex/.apps/games/pcsx2/pcsx2-v2.6.3-linux-appimage-x64-Qt.AppImage.home
/home/lex/.apps/games/pcsx2/pcsx2-v2.6.3-linux-appimage-x64-Qt.AppImage: error while loading shared libraries: libOpenGL.so.0: cannot open shared object file: No such file or directory
lex@home:~$ '/home/lex/.apps/on-line/qBittorrent.AppImage' 
/tmp/.mount_qBittocoBMge/AppRun.wrapped: error while loading shared libraries: libOpenGL.so.0: cannot open shared object file: No such file or directory

• There are ways to do that. From recent experience I've found that most repositories (repos) have their own methods for searching for and finding libraries and dependencies. These systems are far better than they were back in the day (my perspective) but such tools were also always available even back then. Even if you might've had to craft one yourself 🤷‍♀️.

There were always wayz though, too, to get one's job done. I'll try this out on Ubuntu 26.04 and see if I find the same troubles.