Again, I'll be using Riptide for this example. This one is much easier to explain and will, henceforth, be much shorter than the previous part for the Desktop version.

Step 1:

Self-explanatory, right? So on your phone, you are going to scroll down a little until you see a download button.

Step 2:

Again, it's pretty self-explanatory. Click/Tap "Download". This takes you to another page, showing just the picture, now Long Press the picture and some sort of pop-up should come up (be warned, this varies by phone/tablet and browser). As you'll see below.

Step 3:

After Long pressing the screen, a window similar to this should appear (I'm using Opera, which can be found on the Google Playstore). Just click "Save Image". Which takes us to the final step.

Step 4:

Rename the file, if you'd like to and then just tap "Save". Annnnndddd....We're done!

If for some reason you can't download from the mobile DA or the Desktop DA, give me your email so I can send the cover to you. That way, you'll never lose quality from a taken screenshot. ^_<