Fix handling image attachments and animated images in current conversation

[winstona]

Image attachments and animated images would fail to show any message indication when conversation is open despite successfully showing when the conversation is refreshed/reopened.

This adds extra filters for these message types

[cgmcintyr]

Using your fork, images seem to only show the preview rather than the actual image.

I couldn't get images to show using the original master branch, so at least it's a step in the right direction, thanks :)

[p1ho]

The problem this PR addresses is still an ongoing issue. I feel like getting images to show is more important, and the preview problem can be solved in a separate PR as there was a separate issue opened for it. #157

This PR does not address other file types though (video, audio, file still show up as blank message), even though theoretically the handling principle should be the same.