as far i understand your question..
You need to resize the image..
I do it like this, I zoom out the image, select the whole image, cut it and paste it in another New Page (i choose my willing resolution of that new page), then paste the image, and resize it to fit in new page..
Lol, hope u understand..
For transparency:
1. Open your image file.
2. Create a new layer "BELOW" the image layer.
3. Put the image layer selected/active and reduce the opacity.

Hope this helps