This app offers several basic editing features for PDF, including crop, fit, re-size, and encrypt PDF, and add images, among others. Being the default app for viewing documents and images, there is a high chance that you have used it before. If you are a Mac user, then you know what Mac Preview App is. I tried the basic solutions with no success (safe mode, options of visualization, erasing. How to Add Image to PDF with Mac Preview App. This is a real problem when working with hundreds and hundreds of heavy images and affects seriously the normality of the workflow. It always worked good previewing loads of images and this shouldn't happen at all with better and newer Macs. I tried these problematic image files with an old 2008 old Macbook (Leopard) and loads the preview images fast with no problem.
Since a year now I've been working with two new iMacs (Capitan, HighSierra) I noticed that had some problems loading the miniature previews of images files and thought that I just was doing something wrong, but now that I have just bought a new iMac (HighSierra) when I opened fresh new the first thing I tried was transferring my old images to the new one and continues without previewing the thumbnails, to be exact it's not happening with all images the same, there's some technical aspects related to it.
