I might just be weird, but the first thing I'll do is smell and then taste. You'll eventually trust your palette more than anything and in the end you are the final arbiter of your beer. I mean no offence, but pictures are fairly worthless. You've got something on the surface there, maybe a few blobs of yeast, maybe a few colonies of something that you'd rather not be in there, but there is not much of distinctive pellicle (google pellicle for some scary pictures from funky fermentation).
Beer is always full of other things, the idea is to keep the levels of the undesirables low enough so they have little impact on the flavour over the anticipated shelf life of the product. Something has to be seriously wrong on the smell test to stop me putting it in my mouth, but if it passes the sniff then pediococcus, acetobacter, lactobacillus, wild yeast, non-saccharomyces guests hold no fears, you can always spit it out if you don't want to reflect upon the finish. Following that any further curiosity is satisfied with some time if I've got it with the microscope.
I think the grossest thing I do is nibble on additions made directly into the cask once the casks come back to see if there is anything left in them. Cacao nibs that have sat in some old yeast for a few weeks. Pretty much once a week I get handed a glass and asked "is this infected?!" and a quick smell and taste usually answers it.
