Moz Q&A is closed.
After more than 13 years, and tens of thousands of questions, Moz Q&A closed on 12th December 2024. Whilst we’re not completely removing the content - many posts will still be possible to view - we have locked both new posts and new replies. More details here.
How important is the file extension in the URL for images?
-
I know that descriptive image file names are important for SEO. But how important is it to include .png, .jpg, .gif (or whatever file extension) in the url path? i.e. https://example.com/images/golden-retriever vs. https://example.com/images/golden-retriever.jpg
Furthermore, since you can set the filename in the Content-Disposition response header, is there any need to include the descriptive filename in the URL path?
Since I'm pulling most of our images from a database, it'd be much simpler to not care about simulating a filename, and just reference an image id in my templates.
Example:
1. Browser requests GET /images/123456
2. Server responds with image setting both Content-Disposition, and Link (canonical) headersContent-Disposition: inline; filename="golden-retriever"
Link: <https: 123456="" example.com="" images="">; rel="canonical"</https:> -
In theory, there should be no difference - the canonical header should mean that Google treats the inclusion of /images/123456 as exactly the same as including /images/golden-retriever.
It is slightly messier so I think that if it was easy, I'd go down the route of only ever using the /golden-retriever version - but if that's difficult, this is theoretically the same so should be fine.
-
@Will Thank you so much for this response. Very helpful.
"If you can't always refer to the image by its keyword-rich filename"...
If I'm already including the canonical link header on the image, and am able to serve from both /images/123456 and /images/golden-retriever (canonical), is there any benefit to referencing the canonical over the other in my image tags?
-
Hi James. I've responded with what I believe is a correct answer to MarathonRunner's question. There are a few inaccuracies in your responses to this thread - as pointed out by others below - please can you target your future responses to areas where you are confident that you are correct and helpful? Many thanks.
-
@MarathonRunner - you are correct in your inline responses - it's totally valid to serve an image (or other filetype) without an extension, with its type identified by the Content-Type. Sorry that you've had a less-than-helpful experience here so far.
To answer your original questions:
- From an SEO perspective, there is no need that I know of for your images to have a file extension - the content type should be fine
- However - I have no reason to think that a filename in the Content-Disposition header will be recognised as a ranking signal - what you are describing is a rare use-case and I haven't seen any evidence that it would be recognised by the search engines as being the "real" filename
If you can't always refer to the image by its keyword-rich filename, then could you:
- Serve it as you propose (though without the Content-Disposition filename)
- Serve a rel="canonical" link to a keyword-rich filename (https://example.com/images/golden-retriever in your example)
- Also serve the image on that URL
This only helps if you are able to serve the image on the /images/golden-retriever path, but need to have it available at /images/123456 for inclusion in your own HTML templates.
I hope that helps.
-
If you really did your research you would have noticed the header image is not using an extension.
-
Again, you're mistaken. The Content-Type response header tells the browser what type of file the resource is (mime type). This is _completely different _from the file extension in URL paths.
In fact, on the web all the file extensions are faked through the URL path. For example, this page's URL path is:
https://moz.com/community/q/how-important-is-the-file-extension-in-the-url-for-images
It's not
https://moz.com/community/q/how-important-is-the-file-extension-in-the-url-for-images.html
How does the browser know the the page is an html doc? Because of the Content-Type response header. The faked "extension" in the URL path, is unnecessary.
You can view http response headers for any URL using this tool.
-
-
Do you need a new keyboard?
-
@James Wolff: I'm really hoping you're being sarcastic here. As it's totally fine to serve it without the extension. There are many more ways for a crawler to understand what type a file is. Including what @MarathonRunner is talking about here.
-
This isn't accurate. File extension (in the url path) is not the same as the **Content-Type **response header. Browsers respect the response header Content-Type over whatever extension I use in the path.
Example: try serving a file /golden-retriever.png with a content type of image/jpeg. Your browser will understand the file as a .jpg. If you attempt to save, your browser will correct to golden-retriever.jpg.
You can route URLs however you want.
Additionally, I'm not aware of any way browsers "leverage cache by content type". Browsers handle cache by the etag/expires header.
Got a burning SEO question?
Subscribe to Moz Pro to gain full access to Q&A, answer questions, and ask your own.
Browse Questions
Explore more categories
-
Moz Tools
Chat with the community about the Moz tools.
-
SEO Tactics
Discuss the SEO process with fellow marketers
-
Community
Discuss industry events, jobs, and news!
-
Digital Marketing
Chat about tactics outside of SEO
-
Research & Trends
Dive into research and trends in the search industry.
-
Support
Connect on product support and feature requests.
Related Questions
-
How important is it to add hyphens between words in URL Permalink Structure?
We have an issue with our URL Permalink Structures for dynamically generated pages on our website. As we generated hundreds of pages, it does not automatically Space the Words in the Permalink Structure . For example, if we have a product name Under Armour Fire Basketball Shoe , it will show up in the url as: "mywebsite.com/underarmourfire-basketballshoe" vs "mywebsite.com/under-armour-fire-basketball-shoe" How important is it that the URL includes these spaces between each word in the permalink?
Intermediate & Advanced SEO | | NJ-Keith0 -
URL in russian
Hi everyone, I am doing an audit of a site that currently have a lot of 500 errors due to the russian langage. Basically, all the url's look that way for every page in russian: http://www.exemple.com/ru-kg/pешения-для/food-packaging-machines/
Intermediate & Advanced SEO | | alexrbrg
http://www.exemple.com/ru-kg/pешения-для/wood-flour-solutions/
http://www.exemple.com/ru-kg/pешения-для/cellulose-solutions/ I am wondering if this error is really caused by the server or if Google have difficulty reading the russian langage in URL's. Is it better to have the URL's only in english ?0 -
Null Alt Image Tags vs Missing Alt Image Tags
Hi, Would it be better for organic search to have a null alt image tag programatically added to thousands of images without alt image tags or just leave them as is. The option of adding tailored alt image tags to thousands of images is not possible. Is having sitewide alt image tags really important to organic search overall or what? Right now, probably 10% of the sites images have alt img tags. A huge number of those images are pages that aren Thanks!
Intermediate & Advanced SEO | | 945010 -
Should I redirect images when I migrate my site
We are about to migrate a large website with a fair few images (20,000). At the moment we include images in the sitemap.xml so they are indexed by Google and drive traffic (not sure how I can find out how much though). Current image slugs are like:
Intermediate & Advanced SEO | | ArchMedia
http://website.com/assets/images/a2/65680/thumbnails/638x425-crop.jpg?1402460458 Like on the old site, images on the new website will also have unreadable cache slugs, like:
http://website.com/site_media/media/cache/ce/7a/ce7aeffb1e5bdfc8d4288885c52de8e3.jpg All content pages on the new site will have the same slugs as on the old site. Should I go through the trouble of redirecting all these images?0 -
Are backlinks the most important factor in SEO?
I have had an agency state that "Backlinks are the most important factor in SEO". That is how they are justifying their strategy of approaching bloggers. I believe there are a lot more factors than that including Target Market definition, Keyword identification an build content based on these factors. What's everyone's thoughts?
Intermediate & Advanced SEO | | AndySalmons0 -
URL mapping for site migration
Hi all! I'm currently working on a migration for a large e-commerce site. The old one has around 2.5k urls, the new one 7.5k. I now need to sort out the redirects from one to the other. This is proving pretty tricky, as the URL structure has changed site wide. There doesn't seem to be any consistent rules either so using regex doesn't really work. By and large, the copy appears to be the same though. Does anybody know of a tool I can crawl the sites with that will export the crawled url and related copy into a spreadsheet? That way I can crawl both sites and compare the copy to match them up. Thanks!
Intermediate & Advanced SEO | | Blink-SEO0 -
Ending URLs in .html versus /
Hi there! Currently all the URLs on my website, even the home page, end it .html, such as http://www,consumerbase.com/index.html Is this bad?
Intermediate & Advanced SEO | | Travis-W
Is there any benefit to this? Should I remove it and just have them end with a forward slash?
If I 301 redirect the old .html URLs to the forward slash URLs, will I lose PA? Thanks!0 -
Overly-Dynamic URL
Hi, We have over 5000 pages showing under Overly-Dynamic URL error Our ecommerce site uses Ajax and we have several different filters like, Size, Color, Brand and we therefor have many different urls like, http://www.dellamoda.com/Designer-Pumps.html?sort=price&sort_direction=1&use_selected_filter=Y http://www.dellamoda.com/Designer-Accessories.html?sort=title&use_selected_filter=Y&view=all http://www.dellamoda.com/designer-handbags.html?use_selected_filter=Y&option=manufacturer%3A&page3 Could we use the robots.txt file to disallow these from showing as duplicate content? and do we need to put the whole url in there? like: Disallow: /*?sort=price&sort_direction=1&use_selected_filter=Y if not how far into the url should be disallowed? So far we have added the following to our robots,txt Disallow: /?sort=title Disallow: /?use_selected_filter=Y Disallow: /?sort=price Disallow: /?clearall=Y Just not sure if they are correct. Any help would be greatly appreciated. Thank you,Kami
Intermediate & Advanced SEO | | dellamoda2