That's a great picture with the skirt blowing in the wind. When the skirt falls, it will probably look appropriate, but I still wouldn't want to wear it to work--too hard to remember to check that the slit hasn't fallen open every time I fidget. I could go naked all day, but other people might be irritated by too much skin. (I once had so much conflict with someone that we both asked our supervisor to intervene. Turned out that one of the things that bothered her most was a slit on a particular garment. My desk was on a side wall, and it was a side slit, so when she walked past my office and looked in the open door, she saw the wide open slit and was offended, so wouldn't cooperate on work. True story).
That blue jacket is great. I'd wear it over a sheath dress or fit-n-flare. A sheath that fits well shows your shape some without being tight or restricting movement. I think fit-n-flare is as close as I can get to the big, full skirts I love and still look professional.
People at an advertising company might dress more "creatively" than other work environments. For me, that would make it harder to know what's ok, especially bearing in mind that compliments on my clothes could be good or could mean that my appearance is stealing the show from my work. Pay attention to what the women a level or two above you wear--cuts/fit, colors (including how much contrast between colors), whether there is pattern and what type (loud banana leaves/stripes/ subtle stripes/windowpanes, etc). Wear things like what you've seen a few times on people who are respected (but not all the way at the top--the company prez might have license to wear things others shouldn't).
Good luck on your first day!
