While image optimisation isn’t a high priority for brochure style websites, it can be quite important for e-commerce retailers. The correct image optimisation process will increase exposure and decrease load times for your webpage.
- Name images using descriptive plain English
This step is by far the simplest out of all the techniques listed here, yet many people forget to do this. When you upload hundreds of photos from your camera to your pc, you will find that many cameras will give your photos default names like DSC004512.jpg. Search engines crawl not only the text of a webpage but also the file names so naming your photos appropriately allows you the opportunity to use phrasing patterns helping to improve your exposure.
- Use alt tags
Alt tags are what search engines display when images cannot be properly rendered. If you hover your mouse over a photo and see a line of text displayed on screen, this is the alt tag. Alt tags have been found by many experts to be the single most valuable thing in terms of increasing images’ search engine optimisation.
- File sizes
As with other types of content, load times play a factor in determining SEO. Therefore once you have taken your high resolution images, it is important to shrink them using photo editors before uploading to website. Large image sizes cause a drain on the system, slowing load times and causing customers to abandon your site and Google to drop you down the search rankings. A good rule of thumb is to keep your image file sizes below 100kb. Consider this also: Retail giant Amazon has calculated that for every second their website slows down, they lose 1.6 billion dollars a year in lost revenue.
- Choose appropriate image file types
Not all photo file types are created equal. There are three standard file types JPEG, GIF and PNG. Follow the rules of thumbs below for best practice:
- For most situations use JPEGs – they provide the best trade-off between small file size and best quality.
- Never use GIFs for large product images – the file size will be massive and there will be no way to reduce it. Instead use GIFs for thumbnails and decorative images.
- If you can only source PNG images try use PNG–8 over PNG-24.