Encounter PDF documents can not be edited to solve a problem

LP adults urgently need to edit a document, let me help, the file is in PDF format, there are individual background images do not want, need to deal with. So use my Adobe Acrobat Professional 7.0 (Note: This is the professional software used to modify the pdf editing pdf, not the Adobe Acrobat reader that is commonly used to view PDFs). Of course, the TouchUp component is used to process images. Specific method:

1. Click "Tools" - "Advanced Editing Tools" - "TouchUp Object Tool (J)"
2. Click on the image (the image will be selected, there will be a border around the image)
3. Press the Delete button to delete the picture.
4. Click Save.

But when editing the background image, I found that the image is not allowed to be edited. . Is it encrypted? ? ? ? Take a look at the document properties. As shown in the figure:

I am dizzy, I really need a password. I guessed it, calmly think about it, remember to see the PDF decryption software, Baidu took a look, really a lot.
Looking for the most professional. Adult PDF Password Recovery V3.0 revision, as shown in the figure:


Decrypt, then look at the document properties. Figure:


Edit it again, huh, DEL. A mad change. . Finished work! ! !