If you want your website to get fully indexed you should make sure that all spiders have an easy path through you entire website. You can use both images and text links here. If you in your text for example describe how you should make internal links you should make the text a link. In this case I set the links to “Step 5 – Internal links” with the title attribute saying: Learn how to do internal linking.
It’s easy if you think in a visitors point of view. Maybe you read something on your website and all of a sudden a part of the text is a link advising you to read more about something else that is ALSO interesting. Usually you click on the link and read the text, which contains a link getting you to read more…