Well, adding that functionality is a 1 hour job for a professional programmer.
So, basically, "free of charge" for a firm like yours.
Think about it, Opera.

I really do not understand why Opera mail does not permit to paste images from clipboard into the writing area.
In some emails, it matters how you display your message, not just conveying the bytes to the recipient.

Paste and simple resize is all it's needed : select the part of the image with a photo viewer, CTRL C to load that to clipboard and CTRL V to paste it in your email and continue writing.

Keep it simple, Opera, but this simple is TOO SIMPLE.