The movie Transformers: Age of Extinction (which, as a side note, is very bad) features two songs by Imagine Dragons: "Battle Cry" and "All for you". The first one was released on the OST and as a single. I can't seem to find the second one. Not on any soundtrack release or single/album by the band. Is it really not obtainable? (Other than bad quality YouTube videos).
The song "All For You" was a surprise inclusion over the opening scenes of Transformers 4. It was scheduled to be released on CD as part of the soundtrack, but the entire soundtrack got scrapped over licensing rights. As of right now, the only way to obtain it is to rip the audio yourself from the DVD/Blu-Ray. It's not commercially available in any format.