I want to upload a new post where I will have several images. My idea is to make them small in the post, and allow the user to see them bigger using the Simple Lightbox plugin. However, I can't make it work. I press Add media, select the image, select link to either media page or attachment page (according to SLB begginers guide), and then upload the post. I have a link in the image, but it is not displaying any lightbox. Can you help me fixing this issue?