The Part of SEO You Forgot: Image Optimization (Six Tips to Rank Higher)
A picture is only worth a thousand words if someone sees it. In other words, if you’re buried in search results, your images are meaningless.
To ensure your images add value to your digital presence, you need to optimize them appropriately for the web. From alt tags and proper dimensions, to file sizes and file types, we’re digging into the oft-forgotten realm of image optimization.
What is Image Optimization?
Image optimization is the practice of systematically converting images into a web-friendly format without sacrificing quality. The optimization of an image may include reducing file size and dimensions, switching file type, and/or adding relevant titles and alt text.
Ultimately, image optimization helps reduce a site’s load time and ensures images are ADA compliant. When you follow image optimization best practices, you’ll organically improve your search ranking, increase site traffic, and help those with visual impairments use your website effectively.
1. Add Alt Text
Alt text (alternative text), also referred to as alt attributes, are text descriptions of the appearance and/or function of an image on a webpage. Alt-text is a fundamental element of web accessibility and is used by those with visual impairments.
In the event that an image is unable to load, alt text will appear in its place. For SEO, alt text provides more context for search engine crawlers, which helps with indexing. However, alt text should be helpfully descriptive, not grossly stuffed with keywords.
In general, here are the five fundamental alt text best-practices:
Describe the image specifically
Keep it within 125 characters
Include keywords where relevant
Avoid text-heavy images
Don’t include “image of” or “picture of”
Examples Of Alt Text
Weak: alt= “sketchbook”
Average: alt= “person holding colored pencils and sketchbook”
Strong: alt= “person holding colored pencils and a sketchbook with a dinosaur sticker on the cover”
2. Compress Your Images
According to Think With Google, 53% of people will leave a page that takes longer than three seconds to load. For this reason, page speed has become a significant signal when it comes to Google’s search ranking.
However, images comprise 60-65% of bytes on most web pages, and page size is a core variable in page speed. To make sure your site is loading quickly, it’s vital that you compress your images.
At the same resolution in Photoshop, even “medium” compression can shave off up to 95% of the original file size while maintaining high image quality. If you don’t have Photoshop, check out:
3. Follow Platform Guidelines
How you optimize an image is going to depend on where you’re publishing it. For instance, the process for posting on Facebook is going to differ significantly from posting it to your website.
To ensure your images are being displayed at the highest possible quality, you’ll want to follow the specific guidelines of each platform. As a quick reference, here are the best practices for Facebook, Instagram, LinkedIn, Pinterest, and Twitter:
Facebook makes it clear that they automatically resize and format your photo when you upload it. Make sure the Zuckerbergians don’t diminish the quality of your photos by following a few dimension, compression, and file-type tips:
Resize your photos to the following sizes:
Regular photos resolution: 720px, 960px, 2048px wide
Cover photos resolution: 851px by 315px
Avoid Facebook’s compression on your cover photo by ensuring the file size is less than 100KB
Save images as JPEGs with an sRGB color profile
Are your Facebook albums still not looking as clean and crisp as you want them to? Be sure to check the “High Quality” box when you create an album. You can also upload photos in HD from your account settings.
Instagram encourages you to upload your photos at the “best quality resolution possible,” with up to a width of 1080px. While there isn’t much wiggle room with the resolution, Instagram doesn’t specifically limit file size.
Our recommendation: crank up the quality when you save your image. To avoid having to crop your photo on Instagram, check to see that your aspect ratio is between 1.91:1 and 4:5.
Like most social platforms, LinkedIn has different requirements for profile images than they do for sharing a photo. That being said, they’re particularly particular. Here’s the deal:
Photos for your LinkedIn profile should be:
Less than 8 MB
Resolution: Between 400 x 400 px and 7680 x 4320 px
Matt Flowers’ LinkedIn profile to show profile and cover photos
Background photo requirements include:
Less than 8 MB
Recommended Resolution: 1584 x 396 px
Article Images:
Less than 10 MB
Recommended Cover Image Resolution: 744 x 400 px
LinkedIn Page Images Recommended Resolutions:
Logo Image: 300 x 300 px
Cover Image: 1536 x 768 px
Main Image: 1128 x 376 px
Custom Modules: 502 x 282 px
Company Photos: 900 x 600 px
*Acceptable file types for all photos include JPG, GIF, and PNG.*
Pinterest is one of the few social platforms where vertical formats work better. They recommend a 2:3 aspect ratio. Aside from that strange best practice, Pinterest’s requirements are straightforward after that.
File Type: PNG or JPEG
Less than 32 MB
Twitter has clear size and file-type requirements. They support JPEG, GIF, and PNG files formats. However, profile and header photos have different specifications than the images you tweet.
Profile images should be:
Less than 2 MB
400 x 400 px
Header Images:
Less than 2 MB
1500 x 500 px
Sharing a Photo:
Less than 5 MB.
Animated GIFs can be as large as 15 MB on the web (only 5 MB on mobile)
4. Reduce Unnecessary Pixels
Unless you’re a professional photographer, there are few cases where photos need be 5000px wide. Even banner images typically max out at about 2500px wide. To reduce the number of bytes on the page and save the web browser the work of rescaling your image, try to upload it at as close to the natural display size as possible.
For instance, if you have an image that is 1080 x 1080px, but are planning on displaying it at 500 x 500px, take the time to reduce the resolution. To get an idea of how fast unnecessary pixels add up, take a look at this table from Google’s Developer Guide:
| Screen Rolution | Natural Size | Display (CSS px) | Unnecessary Pixels |
|---|---|---|---|
| 1x | 110 x 110 | 100 x 100 | 110 x 110 - 100 x 100 = 2100 |
| 1x | 410 x 410 | 400 x 400 | 410 x 410 - 400 x 400 = 8100 |
| 1x | 810 x 810 | 800 x 800 | 810 x 810 - 800 x 800 = 16100 |
| 2x | 220 x 220 | 100 x 100 | 220 x 220 - (2 x 100) x (2 x 100) = 8400 |
| 2x | 820 x 820 | 400 x 400 | 820 x 820 - (2 x 400) x (2 x 400) = 32400 |
| 2x | 1620 x 1620 | 800 x 800 | 1620 x 1620 - (2 x 800) x (2 x 800) = 64400 |
5. Save Your Images with a Descriptive Name
When you’re working with piles of photos, it’s tiresome to write unique and descriptive names for each one. However, it’s worth it. Google states explicitly, “Google uses the URL path as well as the file name to help it understand your images.”
To optimize your image file name, use both relevant keywords and descriptors. For example, let’s imagine an eCommerce store that specializes in dog gear. Every product page includes a lifestyle photo.
Instead of uploading this photo with the product SKU as the file name, or worse yet, the name right off of the camera, think about how specific people’s searches are. Those in the market for a dog vest might type:
Dog vest for cold weather
Dog vest for medium-sized dogs
Orange dog vest for medium-size dogs
If it’s a popular brand that’s frequently searched, you should also consider including that in the file name. Keep in mind; you’re not writing a novel here, not even a tweet. While file names can extend to 255 characters, we recommend maxing out at 125 characters (even this is more than necessary).
It’s essential to be descriptive without keyword stuffing your file name. Should you try this black-hat SEO, Google may actually flag your page as spam.
6. Use JPEG Whenever Possible
JPEG is a lossy raster format, meaning some detail and quality can be sacrificed to make the file size smaller. When it comes to SEO and load time, small file sizes are your friend. More often than not, even with intricate lines and detail, the visual difference is nearly imperceivable, but the file size is substantially smaller.
PNG 500 x 500 px = 350 KB
JPG 500 x 500 px - 39.1 KB
Search Optimization Services
We’re not photographers at Ethos Copywriting, but we sure know how to ensure images rank well and are accessible to all. If you’re interested in optimizing your site without the time investment, reach out to us by visiting our contact page. We offer both monthly and project-based SEO packages.
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