Images need to be optimised for faster loading on web pages, especially now that more websites are being viewed on tablets, iPads and smart phones.
Most image software will allow you to resize your images and compress them, as well as to change between image types.
If you are looking for some great free tools that are both easy to use and effective then the following is worth a look.
For general batch processing, converting between popular image formats, modes to allow resizing based on height, width, percentage, desktop and more, as well as quick folder or file processing and image file size, then you cannot go past Plastiliq Image Resizer.
As you can see from the images above, you often cannot see any difference between the compressed image and the original, so consider optimising your website’s images to decrease your page loading times – for both usability and SEO reasons.