diff --git a/ElectronClient/gui/NoteText.jsx b/ElectronClient/gui/NoteText.jsx
index a1461ff8ba..04d3516dff 100644
--- a/ElectronClient/gui/NoteText.jsx
+++ b/ElectronClient/gui/NoteText.jsx
@@ -1225,7 +1225,14 @@ class NoteTextComponent extends React.Component {
 			const filePath = filePaths[i];
 			try {
 				reg.logger().info(`Attaching ${filePath}`);
-				note = await shim.attachFileToNote(note, filePath, position, createFileURL);
+				note = await shim.attachFileToNote(note, filePath, position, {
+					createFileURL: createFileURL,
+					resizeLargeImages: 'ask',
+				});
+				if (!note) {
+					reg.logger().info('File attachment was cancelled');
+					continue;
+				}
 				reg.logger().info('File was attached.');
 				this.setState({
 					note: Object.assign({}, note),
diff --git a/ReactNativeClient/lib/components/screens/note.js b/ReactNativeClient/lib/components/screens/note.js
index 16060c9b73..713e7deff7 100644
--- a/ReactNativeClient/lib/components/screens/note.js
+++ b/ReactNativeClient/lib/components/screens/note.js
@@ -419,27 +419,47 @@ class NoteScreenComponent extends BaseScreenComponent {
 		const dimensions = await this.imageDimensions(localFilePath);
 
 		reg.logger().info('Original dimensions ', dimensions);
-		if (dimensions.width > maxSize || dimensions.height > maxSize) {
+
+		let mustResize = dimensions.width > maxSize || dimensions.height > maxSize;
+
+		if (mustResize) {
+			const buttonId = await dialogs.pop(this, _('You are about to attach a large image (%dx%d pixels). Would you like to resize it down to %d pixels before attaching it?', dimensions.width, dimensions.height, maxSize), [
+				{ text: _('Yes'), id: 'yes' },
+				{ text: _('No'), id: 'no' },
+				{ text: _('Cancel'), id: 'cancel' },
+			]);
+
+			if (buttonId === 'cancel') return false;
+
+			mustResize = buttonId === 'yes';
+		}
+
+		if (mustResize) {
 			dimensions.width = maxSize;
 			dimensions.height = maxSize;
+
+			reg.logger().info('New dimensions ', dimensions);
+
+			const format = mimeType == 'image/png' ? 'PNG' : 'JPEG';
+			reg.logger().info(`Resizing image ${localFilePath}`);
+			const resizedImage = await ImageResizer.createResizedImage(localFilePath, dimensions.width, dimensions.height, format, 85); // , 0, targetPath);
+
+			const resizedImagePath = resizedImage.uri;
+			reg.logger().info('Resized image ', resizedImagePath);
+			reg.logger().info(`Moving ${resizedImagePath} => ${targetPath}`);
+
+			await RNFS.copyFile(resizedImagePath, targetPath);
+
+			try {
+				await RNFS.unlink(resizedImagePath);
+			} catch (error) {
+				reg.logger().warn('Error when unlinking cached file: ', error);
+			}
+		} else {
+			await RNFS.copyFile(localFilePath, targetPath);
 		}
-		reg.logger().info('New dimensions ', dimensions);
 
-		const format = mimeType == 'image/png' ? 'PNG' : 'JPEG';
-		reg.logger().info(`Resizing image ${localFilePath}`);
-		const resizedImage = await ImageResizer.createResizedImage(localFilePath, dimensions.width, dimensions.height, format, 85); // , 0, targetPath);
-
-		const resizedImagePath = resizedImage.uri;
-		reg.logger().info('Resized image ', resizedImagePath);
-		reg.logger().info(`Moving ${resizedImagePath} => ${targetPath}`);
-
-		await RNFS.copyFile(resizedImagePath, targetPath);
-
-		try {
-			await RNFS.unlink(resizedImagePath);
-		} catch (error) {
-			reg.logger().warn('Error when unlinking cached file: ', error);
-		}
+		return true;
 	}
 
 	async attachFile(pickerResponse, fileType) {
@@ -494,7 +514,8 @@ class NoteScreenComponent extends BaseScreenComponent {
 
 		try {
 			if (mimeType == 'image/jpeg' || mimeType == 'image/jpg' || mimeType == 'image/png') {
-				await this.resizeImage(localFilePath, targetPath, pickerResponse.mime);
+				const done = await this.resizeImage(localFilePath, targetPath, pickerResponse.mime);
+				if (!done) return;
 			} else {
 				if (fileType === 'image') {
 					dialogs.error(this, _('Unsupported image type: %s', mimeType));
diff --git a/ReactNativeClient/lib/shim-init-node.js b/ReactNativeClient/lib/shim-init-node.js
index 123dc5217a..6d6984f07c 100644
--- a/ReactNativeClient/lib/shim-init-node.js
+++ b/ReactNativeClient/lib/shim-init-node.js
@@ -64,7 +64,16 @@ function shimInit() {
 		}
 	};
 
-	const resizeImage_ = async function(filePath, targetPath, mime) {
+	shim.showMessageBox = (message, options = null) => {
+		if (shim.isElectron()) {
+			const { bridge } = require('electron').remote.require('./bridge');
+			return bridge().showMessageBox(message, options);
+		} else {
+			throw new Error('Not implemented');
+		}
+	};
+
+	const handleResizeImage_ = async function(filePath, targetPath, mime, resizeLargeImages) {
 		const maxDim = Resource.IMAGE_MAX_DIMENSION;
 
 		if (shim.isElectron()) {
@@ -75,9 +84,21 @@ function shimInit() {
 
 			const size = image.getSize();
 
-			if (size.width <= maxDim && size.height <= maxDim) {
+			let mustResize = size.width > maxDim || size.height > maxDim;
+
+			if (mustResize && resizeLargeImages === 'ask') {
+				const answer = shim.showMessageBox(_('You are about to attach a large image (%dx%d pixels). Would you like to resize it down to %d pixels before attaching it?', size.width, size.height, maxDim), {
+					buttons: [_('Yes'), _('No'), _('Cancel')],
+				});
+
+				if (answer === 2) return false;
+
+				mustResize = answer === 0;
+			}
+
+			if (!mustResize) {
 				shim.fsDriver().copy(filePath, targetPath);
-				return;
+				return true;
 			}
 
 			const options = {};
@@ -99,7 +120,7 @@ function shimInit() {
 
 			if (md.width <= maxDim && md.height <= maxDim) {
 				shim.fsDriver().copy(filePath, targetPath);
-				return;
+				return true;
 			}
 
 			return new Promise((resolve, reject) => {
@@ -117,9 +138,15 @@ function shimInit() {
 					});
 			});
 		}
+
+		return true;
 	};
 
-	shim.createResourceFromPath = async function(filePath, defaultProps = null) {
+	shim.createResourceFromPath = async function(filePath, defaultProps = null, options = null) {
+		options = Object.assign({
+			resizeLargeImages: 'always', // 'always' or 'ask'
+		}, options);
+
 		const readChunk = require('read-chunk');
 		const imageType = require('image-type');
 
@@ -155,8 +182,9 @@ function shimInit() {
 
 		const targetPath = Resource.fullPath(resource);
 
-		if (resource.mime == 'image/jpeg' || resource.mime == 'image/jpg' || resource.mime == 'image/png') {
-			await resizeImage_(filePath, targetPath, resource.mime);
+		if (['image/jpeg', 'image/jpg', 'image/png'].includes(resource.mime)) {
+			const ok = await handleResizeImage_(filePath, targetPath, resource.mime, options.resizeLargeImages);
+			if (!ok) return null;
 		} else {
 			// const stat = await shim.fsDriver().stat(filePath);
 			// if (stat.size >= 10000000) throw new Error('Resources larger than 10 MB are not currently supported as they may crash the mobile applications. The issue is being investigated and will be fixed at a later time.');
@@ -177,16 +205,22 @@ function shimInit() {
 		return Resource.save(resource, { isNew: true });
 	};
 
-	shim.attachFileToNote = async function(note, filePath, position = null, createFileURL = false) {
+	shim.attachFileToNote = async function(note, filePath, position = null, options = null) {
+		options = Object.assign({}, {
+			createFileURL: false,
+		}, options);
+
 		const { basename } = require('path');
 		const { escapeLinkText } = require('lib/markdownUtils');
 		const { toFileProtocolPath } = require('lib/path-utils');
 
-		let resource = [];
-		if (!createFileURL) {
-			resource = await shim.createResourceFromPath(filePath);
+		let resource = null;
+		if (!options.createFileURL) {
+			resource = await shim.createResourceFromPath(filePath, null, options);
 		}
 
+		if (!resource) return null;
+
 		const newBody = [];
 
 		if (position === null) {
@@ -195,7 +229,7 @@ function shimInit() {
 
 		if (note.body && position) newBody.push(note.body.substr(0, position));
 
-		if (!createFileURL) {
+		if (!options.createFileURL) {
 			newBody.push(Resource.markdownTag(resource));
 		} else {
 			const filename = escapeLinkText(basename(filePath)); // to get same filename as standard drag and drop
diff --git a/ReactNativeClient/lib/shim.js b/ReactNativeClient/lib/shim.js
index 9912c5ad11..c5ab7ec332 100644
--- a/ReactNativeClient/lib/shim.js
+++ b/ReactNativeClient/lib/shim.js
@@ -220,4 +220,8 @@ shim.pathRelativeToCwd = (path) => {
 	throw new Error('Not implemented');
 };
 
+shim.showMessageBox = (message, options = null) => {
+	throw new Error('Not implemented');
+};
+
 module.exports = { shim };
diff --git a/gulpfile.js b/gulpfile.js
index 860609d803..8ef6c55749 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -44,7 +44,7 @@ gulp.task('watch', function() {
 
 	// For watching, we use the actual tsc tool because it's more robust and
 	// doesn't crash when there's an error
-	const promise = execa('node', ['node_modules/typescript/bin/tsc', '--project', 'tsconfig.json'], { cwd: `${__dirname}` });
+	const promise = execa('node', ['node_modules/typescript/bin/tsc', '--watch', '--project', 'tsconfig.json'], { cwd: `${__dirname}` });
 	promise.stdout.pipe(process.stdout);
 });