[ About downloaded materials ]

Can't open EPS files.

Special vector software is needed to use the EPS file.
Please refer to Article 2 "Download/payment" of the agreement for use details.
It is possible to use it with Adobe Illustrator in a famous point.

What is different when buying it by "Transparent background"?

The file format becomes JPG for usual "Background white", and the background of the material becomes white.
In this case, it is necessary to clip the part where the background is white by hand power, and some image degradation (*) exists because it is JPG form when made and using it.
The file format becomes PNG when the check is put and bought for "Transparent background" and the background becomes transparent. In this case, it has already been transparented and there is no image degradation (*) because it is PNG form even if the background is not clipped when made and using it.
(*)Deterioration by peculiar data compression technology to file format

The figure below is an image of the material graphic overlay with software that can use transparent PNG.
(The figure below is free image-editing software GIMP. )

Though it is thought that the background can be used by clipping, and multiplying and pulling out a white part for myself even in "Background white".

Yes, you may edit like that and use it.
However, the edit in the state of maintaining a high quality because there is no deterioration peculiar to JPG, and the transparents background is possible in case of transparent background (PNG).

The transfer imaging is not transparented

Please Preparate software that can treat transparent PNG file.