Get some Motion Lotion for B&C Oil, its the only stuff I use now.
The chaps are one of the most important pieces of safety equipment you can wear, right after a hard hat, and eye protection. You never know when a branch or top is coming down, and it'll crack a skull in no time. Chaps will bind up the blade of the saw, nearly on contact. I just watched a girl in an equipment operation class put them to good use (first time I've ever seen exactly how they work, really cool actually). She was ripping a decent size spruce (just as a lesson) and didn't realize how far through she was, got to the end and kept pulling on the saw, right into the chaps. The chain bound up almost instantly, and she didn't even tear through them, her jeans underneath were untouched. She won't even touch the saw now if its running poor thing.
What kind of saw were you running, looks like a decent size Husky. If you couldn't tighten the chain more than that you have the wrong size chain, they don't stretch that much, you look like your about 2 links too big (If that really was tightened as far as it would go, I bet you just didn't loosen the clutch cover nuts before you tried tightening it with the adjuster screw).
I hope to god you weren't out there alone doing that, without experience. If I feel uncomfortable with a tree because of lean, size, or deadwood up top I'll ask anyone I know to come watch me, just in case something were to happen its good to have somebody to get help.