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.
Sitespeed: Do images require width and height attributes?
-
Currently working on a sitespeed issue, and was wondering if not having width and height for images actually do cause a problem. We simply Photoshop the resolution we require for the image and add it to the page as is. I though this would actually speed it up, but I am getting from www.gtmetrix.com that we should have them.
What's your experience? Thanks!
-
Just came across a terrific resource that reminded me you'd asked about further reading, Ben.
Check out BrowserDiet for a huge collection of resources about tuning front-end performance of websites. (You'll see #6 talks about exactly your original question)
I can also recommend reading Steve Souder's two books - High Performance Websites and Even Faster Websites - both from O'Reilly. Souders is pretty much the leading specialist in this area. He's the creator of YSlow, one of the primary tools for measuring/analyzing site speed, and is now Head Performance Engineer at Google. His website is SteveSouders.com
That'll be more than enough to get you started. Lemme know if you're still hungry for more!
Paul
P.S. The report details from tests at webpagetest.org can also teach you a huge amount, and there's a forum there run by Patrick Meenan (who built webpagetest) which is just excellent. Patrick frequently answers questions personally.
-
you're welcome, hope your site will be speeding up a lot!!!
-
Yes, thank you. We size them all to what we want on the site so we are good there. Just got done doing it, and it did make a difference. Thanks guys!
-
as Paul correctly said, if your purpose is to improve the page speed just be sure that you're not resizing the images with css/html but that you're uploading the images in that dimensions.
An image of 10241024 resized to 100100 still weights as an 1024 image so my recommendation is to resize all those images to the desired dimensions, moreover if you can use an external cdn you'll save bandwith and have those images loading outside your website. That will help reducing the loadtime of the page.
-
Perfect-O! I completely get it now. Thanks Paul. You da man!
I thought it would be faster as in my mind it was more to read, but now that I understand the loading, I get it. Guess I need to start researching how a website loads. Have any resources I can read, to up my experience with this?
I've been in development but on an application side not website side.
-
The main reason PageSpeed and YSlow recommend including width and height for images is as much the perception of page speed as the actual load time, Ben.
When you include the image dimensions, the browser can draw out the "containers" that will hold the images, reserving the space for them while they download. The browser can then go on the paint the rest of the pages CSS and objects around those "containers" without having to go back and redraw the whole page once the images have downloaded and their sizes are then known.
This gives the user the illusion of a much faster, cleaner page load, and hence the impression of a faster website.
Does that make sense?
Paul
[Edited to add: You should still keep doing what you're doing to produce "size-as" images for your pages. You don't want to be resizing images with the html dimensions, just reporting in html the actual size of the image]
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
-
Removing Toxic Back Links Targeting Obscure URL or Image
There are 2 or 3 URLs and one image file that dozens of toxic domains are linking to on our website. Some of these pages have hundreds of links from 4-5 domains. Rather than disavowing these links, would it make sense to simply break these links, change the URL that the link to and not create a redirect? It seems like this would be a sure fire way to get rid of these links. Any downside to this approach? Thanks,
Intermediate & Advanced SEO | | Kingalan1
Alan1 -
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
Intermediate & Advanced SEO | | dsbud
2. Server responds with image setting both Content-Disposition, and Link (canonical) headers Content-Disposition: inline; filename="golden-retriever"
Link: <https: 123456="" example.com="" images="">; rel="canonical"</https:>1 -
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 -
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 -
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 -
Number of images on Google?
Hello here, In the past I was able to find out pretty easily how many images from my website are indexed by Google and inside the Google image search index. But as today looks like Google is not giving you any numbers, it just lists the indexed images. I use the advanced image search, by defining my domain name for the "site or domain" field: http://www.google.com/advanced_image_search and then Google returns all the images coming from my website. Is there any way to know the actual number of images indexed? Any ideas are very welcome! Thank you in advance.
Intermediate & Advanced SEO | | fablau1 -
Google Not Indexing XML Sitemap Images
Hi Mozzers, We are having an issue with our XML sitemap images not being indexed. The site has over 39,000 pages and 17,500 images submitted in GWT. If you take a look at the attached screenshot, 'GWT Images - Not Indexed', you can see that the majority of the pages are being indexed - but none of the images are. The first thing you should know about the images is that they are hosted on a content delivery network (CDN), rather than on the site itself. However, Google advice suggests hosting on a CDN is fine - see second screenshot, 'Google CDN Advice'. That advice says to either (i) ensure the hosting site is verified in GWT or (ii) submit in robots.txt. As we can't verify the hosting site in GWT, we had opted to submit via robots.txt. There are 3 sitemap indexes: 1) http://www.greenplantswap.co.uk/sitemap_index.xml, 2) http://www.greenplantswap.co.uk/sitemap/plant_genera/listings.xml and 3) http://www.greenplantswap.co.uk/sitemap/plant_genera/plants.xml. Each sitemap index is split up into often hundreds or thousands of smaller XML sitemaps. This is necessary due to the size of the site and how we have decided to pull URLs in. Essentially, if we did it another way, it may have involved some of the sitemaps being massive and thus taking upwards of a minute to load. To give you an idea of what is being submitted to Google in one of the sitemaps, please see view-source:http://www.greenplantswap.co.uk/sitemap/plant_genera/4/listings.xml?page=1. Originally, the images were SSL, so we decided to reverted to non-SSL URLs as that was an easy change. But over a week later, that seems to have had no impact. The image URLs are ugly... but should this prevent them from being indexed? The strange thing is that a very small number of images have been indexed - see http://goo.gl/P8GMn. I don't know if this is an anomaly or whether it suggests no issue with how the images have been set up - thus, there may be another issue. Sorry for the long message but I would be extremely grateful for any insight into this. I have tried to offer as much information as I can, however please do let me know if this is not enough. Thank you for taking the time to read and help. Regards, Mark Oz6HzKO rYD3ICZ
Intermediate & Advanced SEO | | edlondon0 -
Image Maps
Hey forum, I'm curious about Image Maps. Few things I'm not sure about: 1. Will the links be followed? If so, will Google respect rel="nofollow"? 2. Will the image be considered 1 image? (indexed as image, etc.) Or will each map segment be treated as a separate image? 3. Any other SEO pros\cons to consider when adding an image map to an existing page? Thanks, Corwin.
Intermediate & Advanced SEO | | corwin0
