Even if you set the options to not ask where to save files before downloading, Google Chrome always open the Save As dialogue box everytime you want to save an image. There is no other option to save a picture beside the “Save image as…” in the right-click menu.
Save Image to Downloads is a Google Chrome extension that attempts to address the issue. After installed, it adds a new option in the right-click menu that lets you save a picture directly to your download folder. It can save to any folder of your choice but you need to change the location from Google Chrome’s setting page, though.
It worked fine when I tested it on some websites but you can expect it not to be able to save image from certain web pages. Overall, it’s not perfect but it is still a nicer way to download image individually than the built-in option in Google Chrome.
Link: Save Image to Downloads
Another extension to look at is Image Toolbar. When you put cursor over an image, the toolbar appears at the top left corner which provides a direct way to save the picture into your download folder. It also adds the download folders inside the right-click menu.
On a side note, it turns out that Image Toolbar can also save photos in instagram.