Retrieving and Storing Images Linked from Other Domains on Local Server?

Question

(Moderator's note: The original title was "Copy and Paste picture in post without linking to original")

When I copy and paste a picture from another editor window it appears nicely but it links to the original location.

Is there a plugin which lets me copy and paste images in a post (like it happens in Windows Live Writer) so that the image gets uploaded to the uploads dir?

Or is that impossible in a web environment?

Reason: the one thing why I keep returning to Windows Live Writer for initial postings is the image functionality. If I could somehow make this process easier I could write some posts in the WordPress backend instead.

Update: If it does NOT exist yet, I probably will write a plugin on a hook that fires after a new or update of a post, goes through the_content, finds all image url's that are not the same as the preferred root domain (for multisite) and if not, does a cross-load of the image (as e.g. in the swift theme) and then replaces the url with the newly uploaded image. However... since this is a basic thought someone must already have made this I just cant find it in the plugin directory (yet).

Update 2: Let me try this one:

• http://blog.milandinic.com/wordpress/plugins/cache-images/

Update 3: The above plugin works perfectly even in my WordPress Multisite environment.

Answer 1

@Jan:

The cache images plugin: http://blog.milandinic.com/wordpress/plugins/cache-images/ helped me with this, it does not on demand replace the links but rather goes through all links but basically does the same.

One note on this: when I ran it on a small blog it worked pretty well. On another blog (http://edward.de.leau.net) it did a lot of posts but then somewhere in the middle it began replacing ALL images so including the ones that were under http://edward.de.leau.net .... I havent investigated that one I just broke it off. So be careful when you run large batches with this one and keep checking the replace logging screen.

update the new version of the plugin allows on-demand side loading, see: http://weblogtoolscollection.com/archives/2010/11/28/wordpress-plugin-releases-for-1128-2/#comments