I'm generating <img src=
html in a php web-site. The sources of the pictures come from outside sources, like instagram and such (vary). Sometimes, the pictures don't load in the browser and I see an "X" instead of the picture. The image url (right click) points to the right location. If I refresh the page sometimes it does load, sometimes only some, sometimes all the pictures. I don't really understand the pattern.
Can someone point me to possible reasons?
UPDATE due to comments below: How can I check the external server's response? If it failed can I request again? Should I?