when I delete a picture in a received mail (in my inbox), this delete doesn't affect the size of the mail.
I want to gain space by deleting unwanted pictures, but this is useless if the size doesn't change.
Is this a bug of Outlook 2010 or how can you avoid this effect ?
your mail is stored on the server you are just veiwing it from your outlook. so deleting a picture you are veiwing in outlook does nothing to the original message stored on the exchange server. you will have to delete the whole email to reduce space. or you could always create a PST file and move your mail to that freeing up space on the server.