When the backround is erased in photoshop how can i save the picture without backround, because if i save it with no backround later the image is with white backround.?
If you're using Adobe Photoshop the transparency is going to look like a checkered texture on your image. If you save as a .png file the transparency it's going to be maintained if your settings say so.
Example: I took off the background of this drawing:
Then I saved as a .png file with this settings:
When you drag the image from your folder you can see its transparency.