Why are my images not in Googles images search? Why are they ranked so bad? Why took it so long until my images are indexed by Google? This article is exactly about that: how to optimize images for Google Image Search?! It is based on the german version, which I wrote in April 2010. It contains the main and basic tips for images SEO. To keep it simple, the text focuses on the Google image search. But the principles are also useful for other image-search-engines.
In summery you can say: optimizing images for search-engines is like optimizing images for blind people. For those who haven’t the time to read the following epic article here an extract of the essential tips, in order of the importance for the ranking:
- keyword the surrounding text
- keyword in the image name
- image size (min. 320 pixel, max. 1280 pixel)
- keyword in the „alt-text“
- make sure that the image is available for the images-bot
- multiple use of the image (copies)
- multiple links to the image (hot links)
- keyword in the page title (including URL)
- keyword in the title attribute of the image
- keyword relevance of the entire site
- keyword in meta description
- keyword in meta keywords
- position of page in the organic search
- new upload of the same image („actual date“)
Unclear / changing:
- the age of the image (the older the better)
- originality (picture looks different than most of other results)
- specify images in Sitemap
Based on my experience this is it. Its about 80% of the work for a good ranking in Googles image search. Below some comments on the single points…
SEO (search-engine optimization) describes methods to optimize contents for search engines. Finally the content should rank better. Every gallery-webmaster who offers images on websites should optimize for image search. Thanks to the universal search concept, the main Google-result-page includes very often images. And in many cases images are shown on the top of the page. And of course images are eyecatcher. They jump into the users eyes just before the could read the first result.
You should never forget that images optimization is not just for search engines. Many of the following optimization tips are also helpfull for users. Google (that means the Googlebot) is similar to a blind visitor. You can say: if you optimize your picture-gallery for blind users your images have the oportunity to rank on top positions.
The article is divided into three areas. Each section contains important, necessary improvement actions. In addition, some tips are listed, which seems (in my eyes) to be usefull.
1. Onpicture ranking factors
With onpicture factors mean all actions that should be done to the image itself before it’s uploaded. First of all – this should be clear – choose the best images: clear, interesting and beautiful for users. An image should be an „esthetic experience„. The following tips are besides these basic rules of a good picture.
- Image size: Images should be at least 320 pixels and max. 1280 pixels on one length. Smaller images are ranked poor in general, larger images only appear if the user chooses the option „large images „.
- Format ratio. For the best ranking results you should use „normal“ formats: square, 4:3 or up to 16:10. Extremer portrait or landscape formats, however, rank usually bad. This is logically because the result-picture-list looks „ugly“ with these formats.
- Portrait or landscape format? When Google changes in America to the „New Image Search“, the answer to these question changes. Now Google cuts out some images. Because the hight of the images is allways the same it might be better to use Landscape formats. The picture on the resultpage is bigger – and so is the chance to get clicked.
- File name: very important for a successful image-optimization is the file name. Most times a picture can only be found on keyword-phrases that a in the filename (e.g. white-cat.jpg). It makes sense to use more than one term in the filename (e.g. „white-cat-on-green-chair.jpg“). This gives it the chance to rank with „white cat“ or „green chair“ or „cat on chair“ or „green cat“ and so on… However, you should not spam the filename: more than 4-6 words are inappropriate. And of course the name should be a kind of description of what can be seen on the picture.
- Copyright notice: This is irrelevant for images optimization. But I highly recommend this. A picture, that is in the Google index, should not be touched. As an author you should include the copyright notice in the picture before uploading. When it is indexed by Google and someone has done some copies without permission its too late…
- Image type: JPEG, GIF or PNG? I would recommend Jpeg or PNG. My observations are these: Jpeg climbs better in my pictures. I can not prove that statistically. So I would prefer in most cases as a Jpeg compression format. In some cases – particularly b/w graphics – is the compression at the same image quality but with PNG-8 much better. In the cases I use PNG – regardless of ranking, simply upload images faster, which pleased the visitors.
- File size: is basically the question of the compression rate. My experience is that this is not a ranking factor. You should compresse the picture as much as possible without loosing the quality of an image. Usually I worke with photoshop and compress-rate of jpegs is about 60 – 80% of the original. I have no problems with filesizes up to 400 kb.
- Originality: Apparently Google loves the pictures, found the variety. So it is not wrong, previously in the image browser to view the images offered for keyword. The probability that the image climbs climbs well, with its uniqueness. More here about this: „a change in image search – originality as a ranking factor.
Onpage ranking factors
To be successful an image must be well embedded in the HTML page. The following onppage factors describe how to improve an image in the HTML code.
- Surrounding text: The text before and after the image should include one or more times the keyword or the keywords (of the filename). The combination of „keyword file name / keyword surrounding text “ is the lifeblood of a successful image optimization. Surrounding text means about 12 words before and after the picture. You should always look in the source code to prove. Often the code and the css-presentation are completely different.
- Alt-text: Each image should have an alt-text in the image-attribute. This is important not only for search engines, but especially for people with visual impairment. You simply have to make clear: Google is blind and can only understand text.
- Title-attribute: The meaning of the title attribute for the ranking is controversial. By specifying the title-attribute of an image by rolling-over a tooltip appears. Here the user can provide valuable information. If you have a separate caption, the title tag of the image is not necessary. I think the title attribute is a kind of surrounding text. It can increase the keyword relevance.
- Content relevance: Good content is good for images. But actually there are a lot of examples where the pages of good ranking images are lousy. I think Google will change this in the near future.
- Of course it is basically important that the googlebot could find the images. Be sure that your robots.txt allows to crawl the folders including the images.
Summery: A „perfect“ source code looks nearly like this:
... <title>... keyword ...</title> ... <h2>... keyword ...</h2> <p> <img src=".../xxx-keyword-xxx.jpg" alt="... keyword ..." title="... keyword ... - Copyright xyz" width="600" height="450" /> <br /> Image: <strong>... keyword ...</strong> </p> <p>Text bla bla bla keyword. Bla bla bla keywords bla bla bla... keywording ... bla</p>
3. Offpage ranking factors
There are two reasons to optimize images offpage: firstly it’s important for fast indexation of new images. And secondly you can help a picture to rank better by using some „offpage tricks“.
- Internal linking: A good internal linking helps the Googlebot/image to crawl new images. After a long period of „waiting for new images“ Google has changed the indexation frequence. These days it took about 2-4 days until new uploaded images appears in the image-search (jippi, thanks Google :-) )
- Good links to the page: A good link to the page, especially with „powerful“ links, is also useful for images on the page. Naturally „keyword“ relevant links are the best.
- Sitemap: Since some months images can be included in sitemaps. In my observation the sitemap is not important for better indexation or higher ranking – today. But it might become a factor. So I would recommend to use image-sitemaps.
- Copies: if an image is used several times it is a strength signal for Google that this image must be „important„. Copies of pictures are a good way to push up images. But on the other hand its a problem if somebody uses a picture without permission and gets the link in the image-search. This is a typically topic for professional images-seo.
- Hotlinking: Hotlinking is annoying or a tricky optimization method. If you link directly to an image (without embedding an <img>-tag in the html-code) you can steal the link in the image-search-result-page. This is called „hotlinking„. On the one hand, hotlinks shows Google the „importance“ of the image. The problem: if you loose the link in the images-serps you didn’t get any traffic. Exactly the opposite of optimization. It’s a walk on razors edge to allow copies and hotlinking. The art of images-optimization is to control this methods.
- Click-through rate: Usually this is not a factor you can influence. The only thing is to upload attractive pictures. Nice images will be clicked – and often clicked images will rank higher.
Thats it :-)
How long does it take?
If you follow the tips, the images should behave like this:
- Images should be crawled after a few days.
- They appear in the image search after about 2-7 days (actually, this may change again).
- Depending on the „competition“ they should be sorted in between position 50 and 150.
- Then wait and watch it.
- For well-optimized images „move“ slowly upward.
- Good images will climb up after neraly 6 months in the top 18 – visual first page.
- By using offpage-optimization this prozess might be faster.
- The best places on page 1 are ultimately decided by fine-tuning (e.g. it is much better to be on pos. 6 or 7 than to be on pos. 4 or 5.) This „fine tuning“ is not generalizable. It has to be analysed in an individual case.
Good luck! Other views and other tips are very welcome.
Other good articles about image-seo-basics
- Google official advice for optimizing images: „Images„
- Danny Dover from SEOmoz recommends on a furios Whiteboard-Friday nearly the same: „Image SEO Basics – Whiteboard Friday„
- Interesting tips by Spidermarket: „How Image Search Can Entice Users„
- Itsabhik: „[How to] Image Optimization Tips„
- … please help me finding more interesting articles about images basics