Hey,
Looks to me like you're going to want to change one of two things to get those two images to merge. Let me know if I totally missed the boat on this one
. I gave it a shot anyhow.
1. Change the bandanna to look like the autobot logo.
This will require adding shading to the bandanna illustration to match the 3d look of the autobot logo. They never hit pure black (which your bandanna was illustrated in) and there is gradients applied to the different angled surfaces.
I haven't tried my hand at at adding texture and shading fabrics, and this lead me to try an alternate strategy.
2. Easier way - knock back the gradients on the autobot logo so they're a flat black.
This would give the same effect that your bandanna illustration gives, while merging them visually. Tried it out myself and it seems to work fine. You can see what I did here:
Because I don't have the original file I created a mask over the autobot logo with the lassoe tool and copied it up to a new layer. After I had that I could mess with either layer and make the changes without modifying the type I wanted to switch to.
I sized down the bandana to match the edge of the autobot's face (off on the left), and applied a levels edit (brought up the darks, brought down the whites). I think it ties it together nicely. Don't push it too far or it get's nice and grainy.
Since that'll knock the autobot to black it matches the bandanna closer, but since I can't get a really nice selection of your bandanna, I'm just going to hope you have a better selection than I do of it so you an edit the colour to match just that extra bit better.
Hope this helps, I had fun anyways
.