Issues with Rendering of Image Data in PDF

It has come to our attention that an August 2025 update to Acrobat Reader (2025.001.20630) has resulted in embedded JPEG image data within PDF documents being rendered incorrectly when PDF documents are viewed. Images can appear large and blocky, possibly obscuring the text content of the PDF document and making it unreadable.

This issue can impact any PDF documents that include images, irrespective of how they were generated, including those PDF documents that have been created with CoolSpools commands using parameter INCLFILE() to embed a JPEG image. We are among the many organisations to have reported the issue to Adobe, but unfortunately there is little that we can do to help correct the issue, and we are reliant on Adobe delivering a fix.

If you are not seeing this issue on your own desktop or laptop machine, and have a requirement to view PDF documents that include images, then we would recommend not applying any Adobe updates until this issue has been resolved. Remember that even if you are not seeing this issue on your own desktop, if you are distributing PDFs to third-parties, such as customers or suppliers, you will have no control over which version of Acrobat Reader they have installed.

A Possible Workaround

One online thread has suggested that this issue may relate specifically to 24-bit JPEG images, so if you need an urgent workaround then we would recommend opening those JPEG images which you embed into PDF documents using a graphics editing tool, such as Photoshop or GIMP, and saving them as JPEG images with a different bit-depth (i.e. not 24-bit), or as an image in GIF format – for which you would need to update the CoolSpools command parameter INCLFILE() to include the image as *GIF.