Topics Map > Service Catalog > Communications and collaboration services > Instant messaging, presence, voice and video chat
Skype for Business: Change or Add Picture
How to add or modify profile picture shown in skype
The Microsoft documentation for changing/modifying a profile picture can be found here
When you add or change your picture using the directions above you change your picture for your Microsoft 365 profile as well. Outlook, Skype, SharePoint, Delve, etc... will reflect the picture change.