As an academic who has taught this information to post secondary students in the past, I am able to examine how this could be used in my class. The materail would be useful in a range of ways. If used in a class setting where students had access to the site directly, it would be appropriate for students to self pace, with some form of studenet interaction/engagement after. It could be set as a homeworl activity with follow up activity in next class. If used as a link in an online LMS, engagement should be set up via some of feedback/discussion. If used in conjunction with a class dealing with the production of digital images for the web, it would be appropriate to have students explain/jsutify image type and level of compression for the images they are working with.
The concepts presented are in line with other content of this type.
Where it might be improved is to update the material to include the use PNG file type, and also perhaps the SVG image type.
The material will serve as a good resource in relation to preparing digital images for the web.
Language and content can be used at a range of educational levels. For some lower grades some of the language and assumed knowledge may be a bit intense, but the general thrust would provide good background information.
The author spells out the focus of this tutorial and stays within this focus to provide a good overview of the content.
Student would not need the absolutely latest browser as the content will run on a range of older browsers. Speed of connection may be an issue for some of the larger file size images. However, students are alerted to this in the content provided.
Site is straighforward to use with navigation placed consistently. The navigation links are a little small and easy to lose in the rest of thepage, but once found should pose no further navigational problems. After the introduction it might be better to have a "next" button. The use is expected to know that the next link is the next available item in the navigation area. Alternatively, links could be numbered to identifiy an order for reading.