Excessive memory usage (leak?) when there are many photos/videos in conversations

• OS: Guix at commit 8cdecad237343f5c955d17df3a78e41fa1f2d56c.
• Jami version:20211223.2.37be4c3
• What build you are using: Guix

Steps to reproduce

• Can you reproduce the bug: at will
• Steps:
  1. Open a conversation with tens of high resolution photos or videos. 2. Notice RAM memory usage going from 304 MiB (at start) to close to 3 GiB as you scroll through
• Actual result: RAM usage is too high / app becomes sluggish, sometimes gets killed by OOMK
• Expected result: RAM usage should remain reasonable (perhaps load only thumbnails of photos instead of the full thing in memory, if that's what it's currently doing?)