When you "copy" an image in the manner you discuss, you can then paste the image into an email or other compatible app.
Just touch a picture and hold it until the magnifying glass comes out. Let go and the picture will be highlighted plus also have two pull bars on both ends. You can then simply tap the "Copy" bubble that comes out or drag the handles to highlight more words.
After selection, double tap on a search box to make the "paste" command appear. Tap once on the location you want to paste onto and the keyboard will come out. Now touch and hold on the cursor and the "Paste" icon comes out doing this without the keyboard out just brings up the "Select" and "Select All" command.