This must be the thread with the least relevant topic ever here! But I like it!
I think that abbreviations (except those that are actually part of spelling like e. g. or i. e.) are a conventional thing that a community decides about, merely by active usage. So there won't be a "correct" abbreviation for fotolia, so regarding the abbreviation it doesn't matter at all which part of the word is highlighted in which way. And fotolia itself doesn't use an abbreviation for their trademark. I have always used FT, and I have no idea why.