How to stop and start a key frame on a specific time on After Effects?
I understand your problem as follows:

There are three timepoints: T0, T1 and T2.

At T0 you place the image in an initial position.
At T1 you place the first keyframe (position: x1, y1).
And at T2 you have the second keyframe (position: x2,y2).  

You want it to stay at T1 for several seconds before moving on to T2. The easiest way to achieve this is to make a new keyframe at a timepoint several seconds after T1, but before T2. Let's name it T1a.
Now the image will move to x1,y1, stay there until keyframe T1a and then move to position x2,y2.