Thumbnail Images With Nonexistent Sources Are Incorrectly Sized

[adamhb123]

If a thumbnail's image source is unavailable, the element's height is far smaller than the others, throwing off grid sizing and element positioning.

I have a pure-CSS solution to this that may or may not be satisfactory, and will submit a PR soon.

Example:

[jabbate19]

It appears what is happening is Gallery is making a call to S3 for the photo, and S3 is giving a 404 (likely deleted photo). The request needs to be checked beforehand and if it gets a 404, call the refresh