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
-
Underscores, capitals, non ASCII characters in image URLs - does it matter?
I see this strangely formatted image URLs on websites time and again - is this an issue - I imagine it isn't best practice but does it make any difference to SEO? Thanks in advance, Luke
Intermediate & Advanced SEO | | McTaggart0 -
Switching from Http to Https, but what about images and image link juice?
Hi Ya'll. I'm transitioning our http version website to https. Important question: Do images have to have 301 redirects? If so, how and where? Please send me a link or explain best practices. Best, Shawn
Intermediate & Advanced SEO | | Shawn1241 -
Link juice through URL parameters
Hi guys, hope you had a fantastic bank holiday weekend. Quick question re URL parameters, I understand that links which pass through an affiliate URL parameter aren't taken into consideration when passing link juice through one site to another. However, when a link contains a tracking URL parameter (let's say gclid=), does link juice get passed through? We have a number of external links pointing to our main site, however, they are linking directly to a unique tracking parameter. I'm just curious to know about this. Thanks, Brett
Intermediate & Advanced SEO | | Brett-S0 -
Would changing the file name of an image (not the alt attribute) have an effect of on seo / ranking of that image and thus the site?
Would changing the file name of image, not the alt attribute nor the image itself (so it would be exactly the same but just a name change) have any effect on : a) A sites seo ranking b) the individual images seo ranking (although i guess if b) would be true it would have an effect on a) although potentially small.) This is the sort of change i would be thinking of making :  changed to 
Intermediate & Advanced SEO | | Sam-P0 -
How to deal with URLs and tabbed content
Hi All, We're currently redesigning a website for a new home developer and we're trying to figure out the best way to deal with tabbed content in the URL structure. The design of the site at the moment will have a page for a development and within that you can select your house type, then when on the house type page there will be tabs displayed for the user to see things like the plot map, availability and pricing, specifications, etc. The way our development team are looking at handling this is for the URL to use a hashtag or a query string at the end of it so we can still land users on these specific tabs for PPC for example. My question is really, has anyone had any experience with this? Any recommendations on how to best display the urls for SEO? Thanks
Intermediate & Advanced SEO | | J_Sinclair0 -
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 -
Is it safe to redirect multiple URLs to a single URL?
Hi, I have an old Wordress website with about 300-400 original pages of content on it. All relating to my company's industry: travel in Africa. It's a legitimate site with travel stories, photos, advice etc. Nothing spammy about. No adverts on it. No affiliates. The site hasn't been updated for a couple of years and we no longer have a need for it. Many of the stories on it are quite out of date. The site has built up a modest Mozrank value over the last 5 years, and has a few hundreds organically achieved inbound links. Recently I set up a swanky new branded website on ExpressionEngine on a new domain. My intention is to: Shut down the old site Focus all attention on building up content on the new website Ask the people linking to the old site to my new site instead (I wonder how many will actually do so...) Where possible, setup a 301 redirect from pages on the old site to their closest match on the new site Setup a 301 redirect from the old site's home page to new site's homepage Sounds good, right? But there is one issue I need some advice on... The old site has about 100 pages that do not have a good match on the new site. These pages are outdated or inferior quality, so it doesn't really make sense to rewrite them and put them on the new site. I call these my "black sheep pages". So... for these "black sheep pages" should I (A) redirect the urls to the new site's homepage (B) redirect the urls the old site's home page (which in turn, redirects to the new site's homepage, or (C) not redirect the urls, and let them die a lonely 404 death? OPTION A: oldsite.com/page1.php -> newsite.com
Intermediate & Advanced SEO | | AndreVanKets
oldsite.com/page2.php -> newsite.com
oldsite.com/page3.php -> newsite.com
oldsite.com/page4.php -> newsite.com
oldsite.com/page5.php -> newsite.com
oldsite.com -> newsite.com OPTION B: oldsite.com/page1.php -> oldsite.com
oldsite.com/page2.php -> oldsite.com
oldsite.com/page3.php -> oldsite.com
oldsite.com/page4.php -> oldsite.com
oldsite.com/page5.php -> oldsite.com
oldsite.com -> newsite.com OPTION 😄 oldsite.com/page1.php : do not redirect, let page 404 and disappear forever
oldsite.com/page2.php : do not redirect, let page 404 and disappear forever
oldsite.com/page3.php : do not redirect, let page 404 and disappear forever
oldsite.com/page4.php : do not redirect, let page 404 and disappear forever
oldsite.com/page5.php : do not redirect, let page 404 and disappear forever
oldsite.com -> newsite.com My intuition tells me that Option A would pass the most "link juice" to my new site, but I am concerned that it could also be seen by Google as a spammy redirect technique. What would you do? Help 😐1 -
URL Length or Exact Breadcrumb Navigation URL? What's More Important
Basically my question is as follows, what's better: www.romancingdiamonds.com/gemstone-rings/amethyst-rings/purple-amethyst-ring-14k-white-gold (this would fully match the breadcrumbs). or www.romancingdiamonds.com/amethyst-rings/purple-amethyst-ring-14k-white-gold (cutting out the first level folder to keep the url shorter and the important keywords are closer to the root domain). In this question http://www.seomoz.org/qa/discuss/37982/url-length-vs-url-keywords I was consulted to drop a folder in my url because it may be to long. That's why I'm hesitant to keep the bradcrumb structure the same. To the best of your knowldege do you think it's best to drop a folder in the URL to keep it shorter and sweeter, or to have a longer URL and have it match the breadcrumb structure? Please advise, Shawn
Intermediate & Advanced SEO | | Romancing0