How do you get the downsized version of a photo to be the one selected to attach to e-mail?

I have large resolution photos (3. 5 to 4.7 GB +)  which are too large to attach to an e-mail and so I have correctly downsized the 3 or 4 chosen photos to small resolution e.g. 260 KB ready to attach to e-mail to send by e-mail attachment but a message appears on the screen stating "cannot downsize the images" (image numbers not downsized appear as a list) or at best, I can only have access to a single downsized image.  Also, when trying to type the e-mail address of the intended recipient in the e-mail address bar, the keyboard seems to be non-responsive and I cannot type anything in the address bar.  This all appears to have occurred since recent Windows updates were done.