File Name
Before you upload your image it’s worth taking some time to name it – simply describe the subject matter of the picture. Search engines can’t decipher the content based on the picture alone and will look for keywords within your image file name. Keep file names short and unique. Make sure you use dashes (-) between each word (dashes are seen as word separators, avoid using other separators or no separators at all).
For example, miniature-dachshund-long-haired.jpg is a lot clearer and more informative than the original IMG0023.jpg, (after all who would search for IMG0023!)
Remember: File names cannot be changed once you’ve uploaded an image in WordPress, so make sure it’s named correctly first, when still on your computer.
File Format
If you want to keep things straightforward use .jpgs for photographs or images with gradients and plenty of colours and .pngs for simple images with limited colours or when you need to use transparency.
File Size
So you don’t slow page load times down (which is bad for SEO), compress your large images before uploading them. Compression will mean that the image dimensions (width\height) won’t change, but the file size in kilobytes or megabytes will be smaller. Use an image editing program (e.g. Photoshop, Microsoft Office Picture Manager, Picasa, GIMP). Aim for 60-70% quality with .jpg photos, this will probably work well. If there is text in the image you may notice the degradation, so increase the quality to suit. If your program has the option ‘Save for Web’, use it.
Original
60%
20%
Image Size
You can consider cropping your high resolution images to remove unnecessary sections and resizing to reduce the original dimensions. When cropping and resizing the width\height in pixels will change.
300 x 225
150 x 150
Optimising Images in WordPress
Within WordPress you can use a plugin, such as Imsanity or EWWW Image Optimizer (there are many others available) to optimise your images on the fly.
NOTE: Whichever method you use, when optimising your images don’t overwrite your original files, just in case you need to start over.
Alt Text
The Alt Text specifies an alternative text for screen readers of visually impaired visitors to your site, but it’s also used by the search engine to interpret images. Google has indicated that the Alt attribute is the number one element of image SEO.
Use Alt Text that best describes your image and concentrate on it making sense to your visitors – don’t obsess about Google. Do not ever keyword stuff. To illustrate; a good example of Alt Text that could be used for the above picture, ‘Miniature long haired dachshund on Saundersfoot beach’. This is clear, short (four to seven words) and descriptive. Alternatively ‘Small miniature toy long-haired long haired dachshund wiener sausage dog hotdog puppy Saundersfoot beach sands’ is jumbled keyword stuffing and absolutely not recommended.
Make sure each Alt attribute is unique, i.e. don’t keep using the same text over and over. Don’t use Alt Text for images that are used as non functional eye candy (for example borders, spacers, dividers, purely ornamental pictures). You don’t particularly want these indexed by search engines.
Uploading an Image in WordPress
In WordPress it is convenient and easy to add (or amend) your Alt Text using the Media Library:-
- Click to place your cursor in the content where you would like to add your image. Context is important, so place your images within content that is relevant to the image.
- Click on the Add Media button. Select the Upload Files tab to upload a new image or click the Media Library tab to select a previously uploaded image.
- Enter your unique Alt Text on the right hand side. Whilst here you can also add a Title, not so important as the Alt Text in Google’s algorithm, but recommended.
- Finally click Insert into post\page.
Images SEO Checklist
DOs
- If you ignore all the other DOs, do make sure you at least add Alt Text
- Do add a Title
- Do rename your images before uploading, be keyword descriptive, keep it short and only separate words with dashes
- Do compress your images
- Do place your images within related content
DON’Ts
- Don’t repeat the same Alt Text for images, keep them unique
- Don’t add Alt Text to images that are uploaded for only decorative purposes
- Don’t keyword stuff
