The description says it all. When receiving a text with an image (especially one that has a caption or text attached with it) it is very easy to completely miss the image unless you've got the "Tap Notification" setting set to "Opens Textra" instead of "Opens Quick Reply" since the quick reply window is too small by default (the image scrolls past the text window).

My feature request is to show a thumbnail in the floating notification (similar to iMessage on iOS 8) but also to dynamically expand/size the quick reply window to include the larger image preview in the text window. In addition, it would be great to see the image preview in the standard Android pull-down notification menu as well.

These feature enhancements have the benefit of notifying people who don't use quick reply that there was an image but also good for notifying those that don't use the floating notifications that an image was received.