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
-
Inactive Products - Inactive URLs
Hi, In our website www.viatrading.com we have many products that might be in stock or not depending on availability. Until now, when a product was not available anymore, we took this page down (and redirected to its product category page). And, only if the product was available again, we re-activated the URL - this might be days, months or even years later. To make this more SEO-friendly, we decided now that while a product is not available, instead or deactivating/redirecting the page, we will leave it online and just add a message saying "This product is currently not available". If we do this, we will automatically re-activate about 500 products pages at once. 1. Just to make sure, is it harmful for SEO to keep activating/deactivating URLs this way? 2. Since most of these pages have been deindexed for a long time due to being redirected - have they lost all their SEO juice? 3. How can we better activate these old 500 pages - is it ok activating them all at once? Thank you,
Intermediate & Advanced SEO | | viatrading11 -
Image URLs - best practice
Hi - I'm assuming image URL best practice follows same principles as non image URLs (not too many files and so on) - I notice alot of web devs putting photos in subdomains, so wonder if I'm missing something (I usually avoid subdomains like the plague)!
Intermediate & Advanced SEO | | McTaggart1 -
How important is admin-ajax.php?
Hi there! It's been a long time since I last did a technical audit of a site. I've currently playing with the 'fetch as google' tool to find out if we're blocking anything vital. The site is based on Wordpress, and after a recent hacking incident, a previous SEO moved the login portal from domain.com/wp-admin/ to domain.com/pr3ss/wp-admin/ - to stop people finding it. Fair enough. But they then updated the robots.txt file to look like this: User-agent: *
Intermediate & Advanced SEO | | Muhammad-Isap
Disallow: /pr3ss/wp-admin/ Now, some pages are trying to draw on theme elements like: http://www.domain.com/pr3ss/wp-admin/admin-ajax.php
http://www.domain.com/pr3ss/wp-content/themes/bestpracticegroup/images/column_wrapper_bg.png And are naturally being blocked (not that this seems to affect the way pages are rendering in Google's eyes) A good SEO friend of mine has suggested allowing the theme folder, and any sub folders where this becomes an issue. What are your thoughts? Is it even worth disallowing the /pr3ss/wp-admin/ path? Cheers guys and gals! All the best, John. I've found a couple of the theme's0 -
Why is this SERP displaying an incorrect URL for my homepage?
The full URL of a particular site's homepage is something like http://www.example.com/directory/.
Intermediate & Advanced SEO | | TheEspresseo
The canonical and og URLs match.
The root domain 301 redirects to it using the absolute path. And yet the SERP (and the cached version of the page) lists it simply as http://www.example.com/. What gives? Could the problem be found at some deeper technical level (.htaccess or DirectoryIndex or something?) We fiddled with things a bit this week, and while our most recent changes appear to have been crawled (and cached), I am wondering whether I should give it some more time before I proceed as if the SERP won't ever reflect the correct URL. If so, how long? [EDIT: From the comments, see here: https://www.youtube.com/watch?v=z8QKIweOzH4#t=2838]0 -
Attack of the dummy urls -- what to do?
It occurs to me that a malicious program could set up thousands of links to dummy pages on a website: www.mysite.com/dynamicpage/dummy123 www.mysite.com/dynamicpage/dummy456 etc.. How is this normally handled? Does a developer have to look at all the parameters to see if they are valid and if not, automatically create a 301 redirect or 404 not found? This requires a table lookup of acceptable url parameters for all new visitors. I was thinking that bad url names would be rare so it would be ok to just stop the program with a message, until I realized someone could intentionally set up links to non existent pages on a site.
Intermediate & Advanced SEO | | friendoffood1 -
301 Redirection and apostrophes in URLs
Hi I am experiencing trouble getting any redirects with apostrophes in the URLs to 301 redirect in order to eliminate 404 errors. I have tried replacing the instance of the apostrophe in the source URL field to %27 and variations of this but to no avail. The site is a wordpress site (the old URLS are legacies from the old Business Catalyst site) and I am using the redirection plug in. I have gone into some detail with a helpful soul here http://wordpress.org/support/topic/how-to-deal-with-apostrophes-in-source-url but unfortunately to no result. If anyone has any idea how to solve this puzzle I would be grateful for the help. Example: http://www.tesselaars.com/blog/Inside_Flowers/post/Online_Marketing_for_Florists_Part_1%E2%80%93_A_Website_You_Won%27t_Regret/
Intermediate & Advanced SEO | | Seamoose0 -
Where to put a page ID in a URL?
Hello, My company is going to change URLs to example.com/category or example.com/product. When we will change the URLs to product or category pages somehow we have to check whether the requested page is from category table in DB or from products table (this gives much speed to page load time). So we have to choose how to make the different product and category pages.
Intermediate & Advanced SEO | | komeksimas
Programmers said that we need to insert id to URL. So the question is: Which is the better way to place an id to an URL? example.com/product-name?id=111 example.com/product-name/111 example.com/product_name-111 Or maybe we should use some other punctuation mark to separate id from product name? p.s. I have read Dynamic URLs vs. static URLs by Google and it still didn't answered which is the best for all of the pages. Somehow others solve this problem by typing only the names to the URL, but could anyone tell what that technology should be?0 -
How important is the number of indexed pages?
I'm considering making a change to using AJAX filtered navigation on my e-commerce site. If I do this, the user experience will be significantly improved but the number of pages that Google finds on my site will go down significantly (in the 10,000's). It feels to me like our filtered navigation has grown out of control and we spend too much time worrying about the url structure of it - in some ways it's paralyzing us. I'd like to be able to focus on pages that matter (explicit Category and Sub-Category) pages and then just let ajax take care of filtering products below these levels. For customer usability this is smart. From the perspective of manageable code and long term design this also seems very smart -we can't continue to worry so much about filtered navigation. My concern is that losing so many indexed pages will have a large negative effect (however, we will reduce duplicate content and be able provide much better category and sub-category pages). We probably should have thought about this a year ago before Google indexed everything :-). Does anybody have any experience with this or insight on what to do? Thanks, -Jason
Intermediate & Advanced SEO | | cre80