Thanks @binayjha for the reply. Actually we have been creating backlinks for two years. And we have been good so far. Only recently our English keywords have been dropping. So, something must have happened recently. Either in Google or on our site. Can you explain what you mean by strategic backlinks?

Two things,

• Meta description should be optimized. Something like,

Looking instant delivery of FUT Coins? WhatsGaming™ offers cheaper FIFA Coins with secured buying, and 24/7 English Whatsapp support to make in-game purchases.

• To strengthen the long-term competitive position, strategic backlinks required.

Hey, we have a website (whatsgaming.net) and we have been doing SEO for over 2 years now. (on-page, backlinks, social, etc.). Unfortunately we have lost the page 1 positions for the keywords FIFA Coins, Buy FIFA Coins, Cheap FIFA Coins for English pages (the site is multi-lingual). Do you have any idea why it has happened and how to get the keyword positions back? Here's the search console graphs: 

Yes, @binayjha is right. The ALT attribute will index your images in images.google.com which is enough for generating traffic. Also you can tag images in the meta data. But in general, you don't have to rely on the images themselves. You can create a page for every image, with H1, relevant content, internal links, etc. And let those pages become your organic landing pages. This is the best way your audience will be able to find the images and download them.

Besides the alt attribute of image tag, use description of images to tell your users and search engines about the images. Treat each such image like a product in an e-commerce website. Use multiple attributes for the image product and create different URLs of such attribute-rich images. These will help in the images website SEO you required.