Fix/allow PDF files to be uploaded via WYSIWYG image upload process after the SUPEE-9767 security patch changed file validation in Mage_Core_Model_File_Validator_Image.
See StackOverFlow question and answer:
After Magento 1.9 SUPEE-9767 allow pdf upload not working - Invalid Mime Type
Mage_Core_Model_File_Validator_Image(skips validation if mime type isapplication/pdf)Mage_Cms_Model_Wysiwyg_Images_Storage(skips resizing if mime type isapplication/pdf)- Adds
pdfto array ofallowedandimage_allowedextensions
- Install the extension via Composer
- Install the extension via modman
- You can also download from Github and unzip the archive in your project root
Mage_CoreMage_Cms