Created attachment 181671 [details]
Source for generating an animated gif

1. Open attached file. It contains a group of shapes. Select the group.
2. Menu Insert > Media > Animated Image. This opens the "Animation" window.
3. In the "Animation" window select "Bitmap object" option.
4. In the "Image" section click on the right icon, that is the icon with tooltip "Apply Objects Individually".
5. Without any other changes click on "Create" button.
6. Close "Animation" window.
7. The animation is inserted. It should be selected and plays. Move it with Shift+Right arrow a little bit to the right so that it does not overlap with the group.
8. It should be still selected. Menu Format -> Name. Enter a name.
9. Start presentation mode and make sure, that the animation plays.
So this is indeed a functional animated gif.

10. No save the file with a new name and reopen it. Again start presentation mode. You should see an animation.

Error: The image is missing.

That works as described in Version: 5.4.7.2 (x64)
Build ID: c838ef25c16710f8838b1faec480ebba495259d0
CPU threads: 8; OS: Windows 6.19; UI render: default; 
Locale: de-DE (en_US); Calc: CL

But it is broken in Version: 7.5.0.0.alpha0+ (x64) / LibreOffice Community
Build ID: 5df1bb4b1b222be00d25097660c4ee33542896ea
CPU threads: 8; OS: Windows 10.0 Build 19043; UI render: Skia/Raster; VCL: win
Locale: de-DE (en_US); UI: en-US
Calc: CL

With current version the saved file has no image at all. The Picture sub-folder is missing. Such you see a "missing image" frame when reopening the saved file.