Updated EPS mode when opening images without transparency

[Yay295]

1. I moved all EPS images (and images converted from EPS images) to their own folder so that they're all together.
2. I noticed that 1.eps has a BoundingBox of (72, 48), but its ImageData says its size is (100, 67). Pillow currently believes the image size should be (100, 67), so I've added a BMP version of this image at that size to compare it to. However, this comparison does not currently work, because an error occurs when calling Image.tobytes() on the EPS image.

ValueError: No packer found from RGB to 1

[Yay295]

I tried converting "1.eps" to PNG using ImageMagick, and it converted it to a 72x48 sized image. So perhaps Pillow isn't using the right size either. Not that there necessarily is a "right" size, since EPS isn't a raster image format.

[Yay295]

Mode "1" and "L" images should now load as those modes instead of being converted to RGB. "LAB" and "CMYK" are still converted to RGB though.

[radarhere]

I tried converting "1.eps" to PNG using ImageMagick, and it converted it to a 72x48 sized image. So perhaps Pillow isn't using the right size either. Not that there necessarily is a "right" size, since EPS isn't a raster image format.

This is reverting the change requested in #6382 (comment). I'm reluctant to change how Pillow behaves again just because a different third-party application was chosen to compare this against?

[Yay295]

I used ImageMagick because I don't have Photoshop, but I would consider Photoshop to be the one to follow, since EPS is an Adobe creation. I'll remove that commit.

[radarhere]

My list of the changes in this PR.

1. Raise an error if the "BoundingBox" is absent, even if "ImageData" is present
2. Fix loading images where "BoundingBox" occurs after "ImageData"
3. For images without transparency, automatically pick 1, L or RGB mode