I don't think it is a 25" motor or a 15" Transom. It does look like it is about an 1 or so below where the bottom of the Hull would be. The trailer Bunk is interfering with seeing the Hull Lines
Your engine appear to have Power Tilt, maybe even Trim so running with it lifted at low speed is no problem.
At speed you can actually run in Shallower Water than at Idle, but you can't slow down, and there is always the risk of something suddenly being an Obstacle. if I were to chance it, the bottom would have to be like Loon Dung, soft, or fine sand, but Sand will grind away the Prop. We used to have to run Sand Bars(would leave trenchs in the Sand about about 15 inches below the surface) to get the Boat to shore. To get it out, we used to walk it out about 3 hundred feet to where the engine wouldn't drag at idle(didn't have power tilt).