Not sure what's going on with the girl - she looks kind of squashed-up - but you definitely need to remove the white fringing round the spider.
Try this:
- Activate spider layer (I'm assuming you've got it on a separate layer)
- Select Layer > Matting > Remove White Matte (or you could try Defringe)
Or an alternative:
- Ctrl+click on spider layer thumbnail to select all non-transparent content
- Select > Inverse
- Select > Modify > Expand (enter 1 pixel in the dialog)
- Select > Modify > Feather (enter 1 pixel in the dialog)
- Press Delete
This will shave off 1 pixel all the way around, hopefully removing the fringing.