Steam Background not updating

@Jarfinn1 

Try restarting steam, If that doesn't resolve it try this:

1. Right click Apex
2. Go to Manage > Set Custom Artwork
3. Select a random image
4. Right click Apex 
5. Go to Manage > Clear Custom Artwork

@Jarfinn1, @XHelperZ 

Initially, this didn't work. Here's how I have solved it:

1. Closed Steam, also from the taskbar.

2. Opened file explorer at "Steam\appcache\librarycache".

3. Found and deleted the images related to Apex (prefixed with the Apex app id).

4. Restarted Steam.

5. Steam downloaded the correct assets.

6. It can happen that all but one ( [app_id]_library_hero.jpg ) remains the same. In that case, repeat the above for the particular file, without closing Steam and apply @XHelperZ 's solution.