Great plugin, updated for FF 10+ Rated 5 out of 5 stars
Good working version of a great original addon - my favourite screengrab plugin for Firefox (I've tried a lot).
Tested and working with FF 11 beta.
Only improvement I'd make is ensure to strip out invalid characters in the "Save As" filename.
Update 2012-03-07: Alexander has fixed the bug I reported here and submitted new version for AMO approval:
Version 0.96.5c sent on approval in addons.mozilla.org...
Added icon to context-menu
Removed invalid character in filename: \ / : * ? " < > |
Other minor fix in code
Please show example on what url invalid characters in "Save as..."