This needs a two part answer.
1. FR ships out everything as fast as it can. It makes no difference to FR whether the delivery to you is by Fedex or bicycle. From FR's point of view it all left on the same truck.
2. FR does not ship images. It ships a list of addresses for images. Once your browser gets the list of addresses it goes to other web sites to actually get the images. Images make forever to load on your computer, but FR does not know about this.
But your question seems to be about the slowness of your connection, and whether your slow connection can make FR slow.
There has been some speculation that the slowness could be due to thousands of bogus requests made by hackers.