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
-
Having a Keyword in # is not that important in 2018, Do you agree?
Earlier having a Keyword in was one of the important ranking factor or at least every SEO guru use to suggest this. But, of late, we are noticing that Google is not giving much weightage to it. What are your thoughts on this?
Intermediate & Advanced SEO | | SameerBhatia3 -
International Country URL Structure
Hey Guys, We have a www.site.com (gTLD) site, the primary market in Australia. We want to expand to US and UK. For the homepage, we are looking to create 3 new subfolders which are: site.com/au/ site.com/uk/ site.com/us/ Then if someone visits the site.com redirect based on their ip address to to the correct location. We are also looking to setup hreflang tags between the 3 sub-folders and set geo-location targeting in google search console at sub-folder level. Just wondering if this setup sounds ok for international SEO? Cheers.
Intermediate & Advanced SEO | | pladcarl90 -
Lately I have noticed Google indexing many files on the site without the .html extension
Hello, Our site, while we convert, remains in HTML 4.0. Fle names such as http://www.sample.com/samples/index.shtml are being picked up in the SERPS as http://www.sample.com/samples/ even when I use the "rel="canonical" tag and specify the full file name therein as recommended. The link to the truncated URL (http://www.sample.com/samples/) results in what MOZ shows as fewer incoming links than the full file name is shown as having incoming. I am not sure if this is causing a loss in placement (the MOZ stats are showing a decline of late), which I have seen recently (of course, I am aware of other possible reasons, such as not being in HTML5 yet). Any help with this would be great. Thank you in advance
Intermediate & Advanced SEO | | gheh20130 -
Replace dynamic paramenter URLs with static Landing Page URL - faceted navigation
Hi there, got a quick question regarding faceted navigation. If a specific filter (facet) seems to be quite popular for visitors. Does it make sense to replace a dynamic URL e.x http://www.domain.com/pants.html?a_type=239 by a static, more SEO friendly URL e.x http://www.domain.com/pants/levis-pants.html by creating a proper landing page for it. I know, that it is nearly impossible to replace all variations of this parameter URLs by static ones but does it generally make sense to do this for the most popular facets choose by visitors. Or does this cause any issues? Any help is much appreciated. Thanks a lot in advance
Intermediate & Advanced SEO | | ennovators0 -
Links from swf file widely distributed?
Hello, I just realised that Google is listing as backlinks, links from swf games that we created and distributed widely. We never used this method to have backlinks but as we create the games and give them for free to other sites, we added a link back to our site, if the user who played the game want to visit us. But I am worried that this is interpreted as black hat seo, and this affected our ranking badly. Anyone had this kind of issue? How do you think we should be tackling this? Is this could be affected our site? Thanks for your help on this guys 😉
Intermediate & Advanced SEO | | drimlike0 -
Should we use URL parameters or plain URL's=
Hi, Me and the development team are having a heated discussion about one of the more important thing in life, i.e. URL structures on our site. Let's say we are creating a AirBNB clone, and we want to be found when people search for apartments new york. As we have both have houses and apartments in all cities in the U.S it would make sense for our url to at least include these, so clone.com/Appartments/New-York but the user are also able to filter on price and size. This isn't really relevant for google, and we all agree on clone.com/Apartments/New-York should be canonical for all apartment/New York searches. But how should the url look like for people having a price for max 300$ and 100 sqft? clone.com/Apartments/New-York?price=30&size=100 or (We are using Node.js so no problem) clone.com/Apartments/New-York/Price/30/Size/100 The developers hate url parameters with a vengeance, and think the last version is the preferable one and most user readable, and says that as long we use canonical on everything to clone.com/Apartments/New-York it won't matter for god old google. I think the url parameters are the way to go for two reasons. One is that google might by themselves figure out that the price parameter doesn't matter (https://support.google.com/webmasters/answer/1235687?hl=en) and also it is possible in webmaster tools to actually tell google that you shouldn't worry about a parameter. We have agreed to disagree on this point, and let the wisdom of Moz decide what we ought to do. What do you all think?
Intermediate & Advanced SEO | | Peekabo0 -
Does Prefix of my URL make any difference?
Hello, I have a website which is initially appeared in search engine as without www. Last week I made changes in preferred domain name that it appeared with www. In search engine it still shows as without www. I notified to google through webmaster tools that now my domain name is with www but it still shows without www. I want to know that does it affect in SEO and rankings. In Google webmaster tools I added my url with and without www however I kept preferred domain as with www. Do I need to make any extra changes in order to avoid confusion for search engines. Please guide. Thanks
Intermediate & Advanced SEO | | intmktcom0 -
URL rewrites
We have a problem whereby a number of our urls are adressable from different urls - I'm told because of a quirk of developing in .net. e.g. mysite/FundComparison mysite/Fund-comparison mysite/fund-comparison We asked our supplier who hosts this section of our site to do some url rewrites so that the duplicates would 301 to the correct url. They're on IIS 6.0 and are not ready to upgrade to IIS 7.0 (my recommendation, which makes it easier for them to do the rewrite using the rewrite module). They said it would take 6-8 weeks to implement a web controller to do this. "The bulk of the time for this implementation is in the build of the engine + the addition of all the possible permutations of the URL to redirect to the proper URL." This sounds absolutely insane to me. I would have thought it could be done in a matter of hours. What do people think?
Intermediate & Advanced SEO | | SearchPM0