package require http;
package require tls;
 
http::register https 443 ::tls::socket;

# get the HTML page respecting the redirections 
set ncode 0;

while {$ncode == 0 || ($ncode >= 300 && $ncode < 400)} {
    if {[catch {set t [http::geturl $url];} reason options] == 1} {
        return -options $options $reason;
    }

    set ncode [http::ncode $t];
    set meta  [http::meta $t];
    if {$ncode >= 300 && $ncode < 400} {
        set url [dict get $meta location];
        http::cleanup $t;
    }
}

set encoding [lindex [split [split [dict get $meta content-type] ";"] "="] end]
set data     [http::data $t];

http::cleanup $t;

# check for a multi-photo or animated-gif HTML page
set multiPhotoNodes [regexp -inline -all {<\w+\s+(?:\w+="[^\"]*"\s+)*class="(?:(?:\w+(?:\s|-))*)(?:multi-photo\s+photo-\d+)(?:(?:(?:\s|-)\w+)*)"(?:[^>]+)>\s*<img\s+(?:\w+="[^\"]*"\s+)*src="([^\"]+)"([^>]+)>} $data];
if {[llength $multiPhotoNodes]} {
    foreach {whole imgUrl} $multiPhotoNodes {
        # do something with the image URL
    }
} else {
    set animatedGifodes [regexp -inline -all {(?:<img\s+(?:(?:\w+="[^\"]*"\s+)*)src="([^\"]+)"\s+(?:\w+="[^\"]*"\s)*class="\w*(?:\s|-)?animated-gif(?:\s|-)?\w*")|(?:<video\s+(?:\w+="[^\"]*"\s)*class="\w*(?:\s|-)?animated-gif(?:\s|-)?\w*"\s*[^>]*>\s+<source\s+(?:(?:\w+="[^\"]*"\s+)*)video-src="([^\"]+)")} $data]; 
    if {[llength $animatiedGifNodes] == 4} {
        foreach {whole url} $animatedGifodes {
            if {[string match {<img*} $whole]} {
                # process the thumbnail image URL
            } else {
                # process the animated GIF video URL
            }
        }
    }
} else {
    # ...
}