I am starting a tenure-track position soon and writing a NSF CAREER proposal for the first time. I have no preliminary data on this topic; therefore I am using a number of figures from related papers to illustrate my idea.
Without preliminary results, is it a good strategy to use others' figures at this stage (this is a bit philosophical question, but I am little worried about the impression I make with the reviewers)?
I would strongly advise against doing this. Instead, create your own original work that illustrates the main points.
Sometimes I see figures reproduced from a journal article in a grant application. Usually, the figure doesn't work well in that setting. When the grant writer copies the image into the proposal, they typically shrink the image to save space, which makes the image hard to read and understand. Journal article figures are often very complex, making points that are not necessarily relevant to the proposal. It's usually best to create your own figure that says what YOU want to say - to make a point about the science you want to do. Also, I worry that reviewers may regard this as plagiarism.