JA, is that (You)?
What light blue box?
My post was about embedding a video.
Elaborate and I'll try to assist.
I think I get it now.
You're trying to screencap a single post?
On Windows?
Press 'Windows' button on your keyboard.
Start typing 'snip'. (no quotes)
Press Enter after ensuring that 'Snipping Tool' is highlighted/selected.
Press 'New'.
Crop out your intended content.
Then just 'File' 'Save As' and you're done.
Now all that's left to do is to drop that pic into the 'Select/drop/paste file here' box in the 'Quick Reply' windows here on 8ch.