When you are describing something referring to the picture, how to say in academic (textbook) English “It looks something/approximately like this”?
I think the more formal phrase you are looking for is "It bears a [marked] resemblance to <insert reference>."
This phrase is often used in a context where the writer wishes to show a relationship between two articles/objects.
e.g. "For years giant pandas were considered a unique species, however, in the attached image you can see that the giant panda bears/has a [marked] resemblance to the grizzly bear."
However, you said, "For years giant pandas were considered a unique species, however, in the attached image you can see that the giant panda looks something like the grizzly bear." this is more tentative/speculative: more open to another opinion.
Then there are the cases where the first object has no direct comparator and one is invented:
"The graph of solubility looks [somewhat] like a horizontal 'S'." This is OK as you are merely describing it rather than comparing it.
This would be as opposed to:
"The graph of solubility bears/has a [marked] resemblance to that of niobium ferosulfate." (comparison)
"The graph of solubility looks [somewhat] like niobium ferosulfate." (vaguer, more general)