The first thing you need to do is ensure you have the proper signature options defined in your application. In Application Designer, open your new application and use the Select Action->Add/Modify Signature Options. Search for the options listed below. If they do not exist, create them. Whether you create them or not, ensure the security group(s) you want to have access have access to these permissions for your new application.
Option Name: ITEMIMAGE
Description: Add/Update Image
Visible: Enabled
Option Name: SHOWDELETE
Description: Delete Image from Image Library
Visible: Enabled
Then in Application Designer for the application, use the Select Action->Add/Modify Select Action Menu. Ensure the following key exists.
Element Type: OPTION
Key Value: ITEMIMAGE
Position: 950
Subposition: 0
Visible: Enabled
Tabs: MAIN
NOTE: Position & subposition can be changed as you want as long as it's unique.