Why textures exported in PNG are different from JPG format?

[sastun1962]

Hi to all,
I have exported an OBJ with PNG textures and the model (an archaeological structure) have the surface textures "cracked" with thin grey lines...
After a control I have exported the same textures in JPG format and all is good in the final model...
If I compare the same textures, in the PNG format are pieces in a white background, and the JPG textures are connected with a colored shade background.
Why this difference?

[Alexey Pasumansky]

Hello sastun1962,

Texture saved in PNG and TIFF format contain alpha-channel that actually covers the interpolated colors in between the texture atlas charts.

You can remove alpha-channel in Xnview, for example, or adjust 3D viewer settings to not use alpha.

The same case has been already discussed here on forum: http://www.agisoft.ru/forum/index.php?topic=1927

[sastun1962]

Many thanks Alexey!