You have four options:

1. Use the script I provided (untested).
2. Rotate the sprite very slightly. 90.007 (instead of 90) is as close as you're going to get.
3. You could also have the rotation at 270 instead of 90 (for the first one, the pan). You may need flip the texture horizontally though to get it to look right.
4. Use a model instead of a sprite.

The first method takes out the confusion and keeps the accuracy, but you may need some scripting knowledge, mainly just where you can place the code. The second method also does, but is slightly less accurate. If you need high-precision placement of objects (especially in the case of joining two sprites right next to each other), the second option isn't for you. If the first two options aren't for you, the third option retains the accuracy and gets rid of the rotation effect, but requires a simple modification. If the texture is flipped when you have the rotation at 270, then you'll need to do a quick horizontal flip in your graphics edittor. If you don't want to be bothered with the horizontal flip, if there is the need for it, option 4, using a model instead, is just as good. A sprite is nothing more than a model with 4 vertices and two triangles forming a square or rectangle, of which has a texture tossed onto it.