yes, Loki turned himself into a female horse in order to lure away Svaldifari who was owned by a giant placed in charge of building the fortress walls for the price of the sun, moon, and Freya's hand in marriage. When Loki and the others saw that the giant was going to complete the task on time, Loki turned into a mare to seduce the giant's horse (Svaldifari, who was doing the brunt of the work.) As a result, the wall was not completed on time and the sun, moon, and Freya were saved. However, this left Loki pregnant in Mare form, and some time later he gave birth to Sleipnir.
Aww, how sweet. Loki's such a caring mommy. Nice use of keeping Sleipnir's other four legs in shadow. :Nod: Oh, and I just noticed, the bending of the tree trunks looks a lot like the bending of Sleipnir's legs on the cover of the Prose Edda. Was that on purpose or just a coincidence?
Hehe, I noticed the wolf there, must be one of Odin's dogs as Fenrir I don't think was born yet.
Hm, Odin's expression bothers me. He seems very sly and knowing here. Maybe he knows Loki will give him Sleipnir as a gift? Anyway, great job. I love the style and the soft shading.