I originally wrote this back in Feb 2013 as Saving The Unsavable Pictures for my own site - http://hitanykey.webs.com/feb19_2013.html
You see a picture you like on a web page and want to save it on your computer as your wallpaper or background, but when you go to save it the option to save it might not be available. Either through some protection setup or even a glitch in the fabric of the web page itself - here are some ways to work around these issues. All of these examples are from using the Opera browser. Other browsers should have similar options. (My example is from Opera v40)
This would be my first choice. The Save download dialogue box would open. But sometimes the option is grayed out. So in this case I would go to my second choice.
This is what inspired me to write this in the first place. Can't remember what the picture or web site was. Also if you want to save an image from Google's image search, don't right click on the thumbnail and set that because your only going to get a crappy blocky version as the thumbnail is spread out over your monitor. Click on the web page first and get the image directly from that.
I would chose copy then paste it in my photo editing program PhotoFiltre - http://www.photofiltre-studio.com/pf7-en.htm . PhotoFiltre has an option to just right click and Paste as a new image without having to create a new image first.
Use image as theme
This is only for Opera and uses your selected image as a background image for the browser.
Copy image address
This setting gives the actual URL for the image and if you paste it in your browser you might end up on a page by itself. You can then try right clicking and saving.
Use Image On Desktop
Some browsers give you this option. Opera doesn't but Firefox does in a very unique way.
It saves the picture in the following path: C:\Users\Terry\AppData\Roaming\Mozilla\Firefox (replace my name with your own account name).
If you don't know where the saved pictures are stored just right click on your desktop then Personalize then Desktop Background (blue letters bottom left) And it should show you the path for the pic.
Save The Web Page
Opera - Click on Menu, then Page and the Save as..., Webpage, Complete
Firfox - just right click on the web page or File > Save Page As (if you have the menu bar showing), Web Page, complete (*.htm;*.html)
or Ctrl + S usually opens the save options for a number of browsers.
This saves the file on your hard drive in two parts a HTML file and a folder.
For example if I saved my own web page (home page) I would end up with Hit Any Key....html and a folder called Hit Any Key..._files. In the folder will be a number of images associated with the web page and hopefully the one picture your trying to save. Either copy or move the picture (sometimes works for swf files) to a more permanent place on your hard drive and then you can delete the rest. By the way deleting one part, either the HTML or the folder will automatically delete the other if the settings haven't been changed.
The last way is to use, good old-fashioned, Print Screen. Just open up the browser to the picture and then press the PrtSc button on your keyboard. Then open your favourite photo editing program or even Windows paint and paste in your selection. Save it, crop it, edit it....whatever.
There are third party programs that will help you to take screen shots but since Windows Vista, Microsoft has embedded into its system a simple utility called Snipping Tool.
It is pretty simple to use. https://support.microsoft.com/en-us/help/13776