The arm bend looks to be more a result of you wanting to get the bar up into your hips better, which is a better problem to have than trying to actually lift the bar with your arms.
You can try taking your grip out wider as long as it doesn't hurt your wrists and you can hang onto the bar without a problem - that will get the bar to contact higher. But also try really engaging the lats in your start and as the bar passes the knees, really using the lats to push the bar back into your body - this will not just move it back but actually up a bit. If you can do that and also keep your knees back longer, the bar will contact higher toward the hips and you should be able to get away with not bending your arms.
You may find it helpful also to try to use straps and relax your grip as much as you can - that should help keep your arms relaxed during the extension. Once you get the feeling, go back to snatching without straps (you can still do snatches without straps some of the time, and should, but do some of your work w the straps).