SEO relies on your images to load fast and be fully optimised for screens. This is a favourite subject for me, because I am a Graphic Designer I place a lot of importance on my client’s images in their websites. Images speak a thousand words, they create a mood, they give a strong impression, they tell a story and they can convert visitors to your website into sales purely on appeal alone.
If you think you can build a website and knock it together purely from a search marketing perspective, and give no consideration to the visual quality of your website then you are sorely mistaken. I see so many people have websites built by seo companies or adwords people who have NO CLUE about Design and Brand Consistency. This makes me so upset, because I know that these types of websites have been thrown together by some person overseas who has no clue about your business. Your images, ideally should be about YOUR BUSINESS and personal to you. I am not sayingn that every image in your website should be a photograph taken about your business and custom to you, but a mix of your own images plus some use of stock images ( that are carefully selected) will still give an impression that you are real and your business is legitimate.
I do prefer video to tell the story about your business, or explain how to use a particular product, especially complex products like CRMs or variuos gadgets like Cameras etc, but because we are talking about Images I will stick to my subject.
All of your images in your website should be saved as JPEG or PNG files. I normally use PNG files for logos and vector art files. All of my images are saved as JPEG files and are saved for use on the web. I save them at sometimes 2 times the actual size required, but in a low res version of 72 dpi. As an example if I need an image that is 600px X 400px wide, then I would save this from photoshop as an image 1200px X 800px at a resolution of 72 DPI. This will ensure that the image is sharp, but the resolution is still low and it will load much faster. You can save your images at 150% or 100% of the required size, but I like to make sure its nice and sharp so I go for 200% of the final size. I am very fussy about the images and the content of my sites, and I always ask clients if they are either willing to spend money on a good copywriter or atleast pay a little extra for me to re-write their copy into a more web appealing.