Very often, the owners of commercial projects neglect such source of traffic as search by images. Someone accidentally closes the image from being indexed by robots.txt, others forget to sign pictures of goods, and others use uninformative signatures like common phrases or the word "photo". I propose to remedy this situation and to optimize the signature so that it may give an additional targeted traffic. If we are talking about commercial sites, the people who came through the image search can do not have an informative intent. Often these people have a commercial purpose, but they do not know how looks a particular product (for example, " knife for cutting lemon " or "copper beads"). Or they are looking for a model of the liked pictures ("chair for toddler", " homemade soap"). The first thing you have to take care to get all this traffic is to tell the search engines, using the attribute ALT, what is in the picture. But you need to do it as it would be looking for your customers. For example, how can you sign the photo given below if you have a clothing store for babies?
Typically, online shops contain several product images at different angles so that you can examine it in detail. What have to do with the signature in this case? The easiest way is to leave the same description for all photos. The uniqueness of the photos is more important for image SEO. And it is clear for understanding that on the photos of the item card probably shown the same thing. It's purposeless to describe carefully. You can only add to the main text: "View 1", "View 2" and so on.
Imagine that you have a number of different caps?
How to be with descriptions of images in this case? Because of hard describing the image in detail, you can use the same ALT, such as "Winter cap with a pompon". Google will show different photos from the same site in view of their uniqueness and the total number of good pictures in the network on this topic. For the names/titles worth spending the time to make them unique for each cap: add a brand, color, the presence of some chips or other characteristics. But it is not so important for the ALT tag in this case.
In the online store, image are repeated on the product card and in the category to which it belongs. How to be in this case? Should it be written unique ALT for a single image on different pages? Here, a similar situation, ALT images in the category can be left in the same (so often makes most online stores), as well as on the item card. And then, depending on the query, the search engine will return the most relevant document. ALT attribute to the IMG tag is essential in the search for images in Google. And whether it helps to rank in standard organic search results? Judging from the data of the experiments, Google uses ALT as plain text, and if you are using unique keywords, then it will be a document with a picture.
TITLE attribute of the image never taken into account by Google(check also The Often Overlooked Components Of SEO). It is better to use for usability than for signing of images, cause to write there something different from ALT will be difficult if the site contains thousands of pictures. In other words, I would recommend not to use any title = "", or duplicate it with alt = "". Or you need to prescribe unique titles for images other than the ALT, but also beautiful, briefly and clearly describe the pictures. But in our opinion, the last is too much.