A trick that I've always found effective to getting much stronger is not over-repping warm up weights. I have increased my weights significantally over the past few months using this method.
On chest days when I bench, I warm up with about 3 reps of 135, then relax for about a minute or two, have some water (not too much though) move up to 155 and do 3 of those. Then I take about a 2 minute break and stretch it out a bit. After that I move up to 185 and do that three times, break for a few minutes, move up to 205, 225, 245, 265, 285, (smaller breaks and 2 reps after 205.) Then I go to what I think would be my max and add about 10 pounds. For instance, I thought my max would be 305, then I added 10 to 315. I was able to get one in, so I immediately dropped down to 285 and did 5 of those.
The reason being is that you want to get comfortable with the heavier weights. A lot of confidence is added when you know that you have the weight securely in your hands. I know it may sound odd and not work for everyone, but give that a shot with your warm-up weights and see if you can work your way up faster. Also with this method, you allow your muscles to get comfortable with weight, but not over-tired by doing too many reps.
Also, you may gain a bit of fat when gaining strength, it's really hard to stay super lean when gaining any weight and strength, but from your pics, it doesn't look like gaining a small amount of fat will be a problem.
(I appologzie for some poor grammar and spelling; reason: phone)