See memory usage in the manual. A better option is separate object for each image, or at least a small number of pages per object. Then Construct will be able to load only some images at a time and leave the others out of memory, and you can also use the system actions to load/unload object images if needed. If you have all pages in the same object, then Construct will load everything in to memory, and it will be slow and have an extremely high memory usage.
Loading dynamically from URLs is another option - you could import all your pages as image files in the project 'Files' folder, and load them one at a time from there, which will also avoid having them all in memory at the same time (as loading an image from a URL to a Sprite will replace the current image).