As far as the codes that haven’t been introduced, are you referring to the img src tag? That tag is introduced on lesson 7 bubble 1 map level and then again in bubble 2 BUT on bubble 2, you do need to dig in a little bit. You have to click on the arrow to expand the topic “How do I add images?”. I have attached a screenshot. However, you may be referring to another tag not introduced?
As far as learning to search properly, are you referring to media literacy? You may know there is a lesson on web searching techniques in lesson 12. I completely understand your point on the order as it relates to searching for pictures. You can make a suggestion to https://support.code.org/ regarding this. For my class, I have a student demo how he searches for a picture in Creative Commons (the more techie parts such as saving to computer and uploading to Code.org) and we also discuss basic search techniques at that time.