SEO difference of img and anchor tag

Question

Lately I have the constant the struggle of images being too large for the x device or too small for the y device or too many for the z device.

In reality, the problem is that, as long as there is an img with a proper src in a web page, it has to be rendered by the browser, you have no option nor power to control that.

Loading your images asynchronously will solve this problem but it will cost to SEO.

So I came with the idea of just including all the possible (or necessary) images as anchors with links to those images instead, and then, depending on the device, present to the user only the images that he needs to see.

That way, I won't force the user to download unnecessary images and I will still have a reference to those images in my page for SEO purposes.

So, how do search engines handle img tags and anchors with links to images? Is there a big difference in SEO value between them?

Considering of course that an img will be replaced by an anchor with the img's src as href, the title as title and the alt as content.

Answer 1

There will be a difference.

To begin, any link value, semantic or otherwise, is primarily given to the target resource, typically a page, however, in your case an image file. This is not absolute, of course, since links can also indicate the topic of the page that links to the resource.

In the case of a link to example.com/chrysler/300/2012-chyrsler-300.jpg, the semantic value would be chrysler(2) 300(2) 2012(1). These values best describes the resource, an image, and can give clues to the page linking to the resource. URLs are weighed rather heavily in SEO. This includes links. This means that any link to a page or other resource would normally have it's link and semantic value primarily passed to the target though not exclusively. The semantic value would also be used in image search.

As for image tag alt text, things are different. In this case, no link value is passed to the resource, however, the semantic value of the alt text and URL are used to understand the image and the page that the images are on. This helps with the semantic value of the page the image is used on and in image search.

The primary difference would be that using an image tag would place the greater semantic value on the page with the image, and a link to an image would place greater semantic value on the image and less to the page. Replacing image tags with links could reduce the semantic value of the page which, depending upon the remaining semantic clues of the page, may make a large difference or little to none at all. However, the value of the images may increase if you are concerned with image search.

While I would not normally suggest that anyone change image tags for links, for a page with a lot of images, this could be a viable solution to help reduce load times and potentially increase image search. Where the lines are drawn, only a search engineer can tell you specifically.