I'm requesting a feature to copy the current image to clipboard, it will come really handy to use in other programs without saving the image as an intermediate file.
Lan,
Yes, this feature request, I think is valid. I do not know of a capture image option inside AVIdemux.
Did you know, you can capture the AVIDemux window only to clipboard with your OS?
Windows: Alt [Print Screen] then Ctrl V into any image editing program including mspaint.
Mac: https://duckduckgo.com/?q=Mac+Capture+window+image+keys&ia=web
Linux: also has a similar feature. Look up per which OS and GUI you are running.
Making a screenshot of Avidemux window is often useless for the purpose of obtaining the current picture as it is often downscaled, upscaled to match the screen scaling factor in HiDPI conditions or both.