diff --git a/src/lib/blob-helpers.js b/src/lib/blob-helpers.js
index 2639478c..1ebf34c4 100644
--- a/src/lib/blob-helpers.js
+++ b/src/lib/blob-helpers.js
@@ -66,10 +66,58 @@ export function fileNameForMime(fname, mime) {
   return fname + '.' + ext;
 }
 
+// Scale uploaded image to fit under certain dimensions or byte size, optionally constraining to a square.
+export function imageFileScaled(file, maxWidth, maxHeight, maxSize, forceSquare, onSuccess, onError) {
+  const img = new Image();
+  img.crossOrigin = 'Anonymous';
+  img.onerror = function(err) {
+    onError("Image format unrecognized");
+  }
+  img.onload = function() {
+    // Once the image is loaded, the URL is no longer needed.
+    URL.revokeObjectURL(img.src);
+
+    // Calculate the desired image dimensions.
+    const dim = fitImageSize(this.width, this.height, maxWidth, maxHeight, forceSquare);
+    if (!dim) {
+      onError("Invalid image");
+      return;
+    }
+    let canvas = document.createElement('canvas');
+    canvas.width = dim.dstWidth;
+    canvas.height = dim.dstHeight;
+    const ctx = canvas.getContext('2d');
+    ctx.imageSmoothingEnabled = true;
+    ctx.drawImage(this, dim.xoffset, dim.yoffset, dim.srcWidth, dim.srcHeight,
+      0, 0, dim.dstWidth, dim.dstHeight);
+
+    let mime = SUPPORTED_IMAGE_FORMATS.indexOf(file.type) < 0 ? 'image/jpeg' : file.type;
+    let imageBits = canvas.toDataURL(mime);
+    const parts = imageBits.split(',');
+    // Get actual image type: 'data:image/png;base64,'
+    mime = getMimeType(parts[0]);
+    if (!mime) {
+      onError("Unsupported image format");
+      return;
+    }
+    // Ensure the image is not too large. Shrink the image keeping the aspect ratio.
+    while (base64DecodedLen(imageBits.length) > maxSize && quality > 0.45) {
+      imageBits = canvas.toDataURL(mime, quality);
+    }
+
+    canvas.toBlob((blob) => {
+        onSuccess(blob, mime, dim.dstWidth, dim.dstHeight, fileNameForMime(file.name, mime));
+      }
+    );
+    canvas = null;
+  };
+  img.src = URL.createObjectURL(file);
+}
+
 // Convert uploaded image into a base64-encoded string possibly scaling
 // linear dimensions or constraining to a square.
 export function imageFileScaledToBase64(file, width, height, forceSquare, onSuccess, onError) {
-  var img = new Image();
+  const img = new Image();
   img.crossOrigin = 'Anonymous';
   img.onerror = function(err) {
     onError("Image format unrecognized");
@@ -100,7 +148,7 @@ export function imageFileScaledToBase64(file, width, height, forceSquare, onSucc
       return;
     }
     // Ensure the image is not too large
-    var quality = 0.78;
+    let quality = 0.78;
     if (base64DecodedLen(imageBits.length) > MAX_INBAND_ATTACHMENT_SIZE) {
       mime = 'image/jpeg';
     }
diff --git a/src/views/messages-view.jsx b/src/views/messages-view.jsx
index f1628c1f..2df2963c 100644
--- a/src/views/messages-view.jsx
+++ b/src/views/messages-view.jsx
@@ -624,6 +624,9 @@ class MessagesView extends React.Component {
     }
   }
 
+  // Send attachment as Drafty message:
+  // - if file is too large, upload it and send a s link.
+  // - if file is small enough, just send it in-band.
   sendFileAttachment(file) {
     if (file.size > MAX_INBAND_ATTACHMENT_SIZE) {
       // Too large to send inband - uploading out of band and sending as a link.
@@ -647,6 +650,7 @@ class MessagesView extends React.Component {
     }
   }
 
+  // handleAttachFile method is called when [Attach file] button is clicked.
   handleAttachFile(file) {
     if (file.size > MAX_EXTERN_ATTACHMENT_SIZE) {
       // Too large.
@@ -662,16 +666,9 @@ class MessagesView extends React.Component {
     }
   }
 
-  sendImageAttachment(caption, mime, bits, width, height, fname) {
-    let msg = Drafty.insertImage(null, 0, mime, bits, width, height, fname);
-    if (caption) {
-      msg = Drafty.appendLineBreak(msg);
-      msg = Drafty.append(msg, Drafty.init(caption));
-    }
-    this.props.sendMessage(msg);
-  }
-
-  handleAttachImage(file) {
+  // sendImageAttachment sends the image bits inband as Drafty message.
+  sendImageAttachment(objectUrl, caption, mime, width, height, fname) {
+    // Upload or scale the image.
     // Check if the uploaded file is indeed an image and if it isn't too large.
     if (file.size > MAX_INBAND_ATTACHMENT_SIZE || SUPPORTED_IMAGE_FORMATS.indexOf(file.type) < 0) {
       // Convert image for size or format.
@@ -680,7 +677,6 @@ class MessagesView extends React.Component {
         (bits, mime, width, height, fname) => {
           this.setState({imagePreview: {
             url: URL.createObjectURL(file),
-            bits: bits,
             filename: fname,
             width: width,
             height: height,
@@ -713,6 +709,31 @@ class MessagesView extends React.Component {
         }
       );
     }
+
+    let msg = Drafty.insertImage(null, 0, mime, bits, width, height, fname);
+    if (caption) {
+      msg = Drafty.appendLineBreak(msg);
+      msg = Drafty.append(msg, Drafty.init(caption));
+    }
+    this.props.sendMessage(msg);
+  }
+
+  // handleAttachImage method is called when [Attach image] button is clicked.
+  handleAttachImage(file) {
+    let size = file.size;
+    // If image is too big scale it down before previewing.
+    if (size > MAX_EXTERN_ATTACHMENT_SIZE) {
+    }
+
+    // Launch image preview screen.
+    this.setState({imagePreview: {
+      url: URL.createObjectURL(file),
+      filename: fname,
+      width: width, // FIXME: width is not defined.
+      height: height, // FIXME: height is not defined.
+      size: size,
+      type: mime // FIXME: mime type is not defined.
+    }});
   }
 
   render() {
diff --git a/src/widgets/image-preview.jsx b/src/widgets/image-preview.jsx
index 8232fc72..aa16a861 100644
--- a/src/widgets/image-preview.jsx
+++ b/src/widgets/image-preview.jsx
@@ -30,7 +30,7 @@ export default class ImagePreview extends React.PureComponent {
 
   handleSendImage(caption) {
     this.props.onClose();
-    this.props.onSendMessage(caption, this.props.content.type, this.props.content.bits,
+    this.props.onSendMessage(caption, this.props.content.type,
       this.props.content.width, this.props.content.height, this.props.content.filename);
   }
 
@@ -47,7 +47,7 @@ export default class ImagePreview extends React.PureComponent {
     size.maxHeight = '100%';
 
     let filename = this.props.content.filename;
-    // Averate font aspect ratio is ~0.5; File name takes 1/3 of the viewport width.
+    // Average font aspect ratio is ~0.5; File name takes 1/3 of the viewport width.
     const maxlength = Math.max(((this.state.width / REM_SIZE / 1.5) | 0) - 2, 12);
     if (filename.length > maxlength) {
       filename = filename.slice(0, maxlength/2 - 1) + '…' + filename.slice(1 - maxlength/2);