Can't paste image from website

For example:

https://community.st.com/t5/stm32cubeprogrammer-mcus/stm32-cube-programmer/m-p/660800/highlight/true#M6204 

I wanted to post the picture of the NUCLEO-F446RE from the ST Product Page. So I right-clicked the image on that page, and chose 'Copy Image':

Then went back to the forum, and pasted into the composition window - and got the error shown (there's multiple errors because I retried a few times).

I even tried opening the image in a separate tab, and copying from that:

https://www.st.com/bin/ecommerce/api/image.PF262063.en.feature-description-include-personalized-no-cpn-medium.jpg 

Same error.

The workaround was to copy into my image editor, then immediately copy again from there, and paste into the post.

This has been happening increasingly lately.