The provided file outline.png doesn't seem to be transparent - at least I got this error message in Microsoft Teams ToolKit In VS Code when I tried to run validation ...

Choose from Dinosaur Outline Clip Art stock illustrations from iStock. Find high-quality royalty-free vector images that you won't find anywhere else. Video Back Videos home Signature collection ...

Choose from Elephant Outline Clip Art stock illustrations from iStock. Find high-quality royalty-free vector images that you won't find anywhere else. Video Back Videos home Signature collection ...