diff --git a/umbra/behaviors.d/instagram.js b/umbra/behaviors.d/instagram.js
new file mode 100644
index 0000000..8955fbc
--- /dev/null
+++ b/umbra/behaviors.d/instagram.js
@@ -0,0 +1,137 @@
+// {"url_regex":"^https?://(?:www\\.)?instagram\\.com/.*$", "request_idle_timeout_sec":10}
+//
+// vim:set sw=8 et:
+//
+
+var umbraInstagramBehavior = {
+        IDLE_TIMEOUT_SEC: 20,
+        idleSince: null,
+        state: "loading-thumbs",
+        imageCount: null,
+        bigImagesLoaded: 0,
+        currentBigImage: null,
+        previousBigImage: null,
+
+        intervalFunc: function() {
+                if (this.state === "loading-thumbs") {
+                        if (window.scrollY + window.innerHeight < document.documentElement.scrollHeight) { 
+                                window.scrollBy(0, 200);
+                                this.idleSince = null;
+                                return;
+                        } 
+
+                        var moreButtons = document.querySelectorAll(".PhotoGridMoreButton:not(.pgmbDisabled)");
+                        if (moreButtons.length > 0) {
+                                console.log("clicking load more button");
+                                moreButtons[0].click();
+                                this.idleSince = null;
+                                return;
+                        } 
+                        
+                        if (this.idleSince == null) {
+                                console.log("nothing to do at the moment, might be waiting for something to load, setting this.idleSince=Date.now()");
+                                this.idleSince = Date.now();
+                                return;
+                        } else {
+                                var doneButtons = document.querySelectorAll(".PhotoGridMoreButton.pgmbDisabled");
+                                if (Date.now() - this.idleSince > 9000 || (doneButtons.length > 0 && doneButtons[0].innerText === "All items loaded") ) {
+                                        console.log("finished loading-thumbs, it appears we have reached the bottom");
+                                        this.state = "clicking-first-thumb";
+                                        this.idleSince = null;
+                                        return;
+                                } else { 
+                                        // console.log("still might be waiting for something to load...");
+                                        return;
+                                }
+                        } 
+                } 
+
+                if (this.state === "clicking-first-thumb") {
+                        var images = document.querySelectorAll("a.pgmiImageLink");
+                        if (images && images !== "undefined") {
+                                this.imageCount = images.length;
+                                if (images.length > 0) {
+                                        console.log("clicking first thumbnail");
+                                        images[0].click();
+                                        this.idleSince = null;
+                                        this.state = "waiting-big-image";
+                                        return;
+                                }
+                        }
+
+                        console.log("no big images to load?");
+                        this.idleSince = Date.now();
+                        return;
+                }
+
+                if (this.state === "waiting-big-image") {
+                        if(this.currentBigImage == null) {
+                                var imageFrame = document.querySelectorAll("div.Modal div.Item div.iMedia div.Image");
+                                if (imageFrame.length > 0 && imageFrame[0].getAttribute("src") !== this.previousBigImage ) {
+                                        this.currentBigImage = new Image();
+                                        this.currentBigImage.src = imageFrame[0].getAttribute("src");
+                                        //console.log("this.currentBigImage.naturalWidth=" + this.currentBigImage.naturalWidth + " this.currentBigImage.src=" + this.currentBigImage.src);
+                                        return;
+                                } else if(this.idleSince == null ) {
+                                        console.log("waiting for image frame to load");
+                                        this.idleSince = Date.now();
+                                        return;
+                                }
+                        } else if (this.currentBigImage.src !== this.previousBigImage && this.currentBigImage.naturalWidth !== 0) {
+                                console.log("next big image appears loaded, will click right arrow next time");
+                                this.state = "click-next-big-image";
+                                this.previousBigImage = this.currentBigImage.src;
+                                this.currentBigImage = null;
+                                this.bigImagesLoaded++;
+                                this.idleSince = null;
+
+                                if (this.bigImagesLoaded >= this.imageCount) {
+                                        console.log("looks like we're done, we've loaded all " + this.bigImagesLoaded + " of " + this.imageCount + " big images");
+                                        this.state = "finished";
+                                        this.idleSince = Date.now();
+                                }
+                                return;
+                        } else if(this.idleSince == null) {
+                                console.log("Waiting for big image to load");
+                                this.idleSince = Date.now();
+                                return;
+                        }
+
+                }
+
+                if (this.state === "click-next-big-image") {
+                        var rightArrow = document.querySelectorAll("a.mmRightArrow");
+                        if (rightArrow.length > 0) {
+                                // console.log("clicking right arrow");
+                                rightArrow[0].click();
+                                this.state = "waiting-big-image";
+                                this.idleSince = null;
+                                return;
+                        } else {
+                                console.warn("no right arrow to click?? weird");
+                                this.idleSince = Date.now();
+                                return;
+                        }
+                }
+        },
+
+        start: function() {
+                var that = this;
+                this.intervalId = setInterval(function(){ that.intervalFunc() }, 50);
+        },
+
+        isFinished: function() {
+                if (this.idleSince != null) {
+                        var idleTimeMs = Date.now() - this.idleSince;
+                        if (idleTimeMs / 1000 > this.IDLE_TIMEOUT_SEC) {
+                                return true;
+                        }
+                }
+                return false;
+        },
+};
+
+// Called from outside of this script.
+var umbraBehaviorFinished = function() { return umbraInstagramBehavior.isFinished() };
+
+umbraInstagramBehavior.start();