feat(gui): Display image size when drive too small

This adds a display of the determined image size to the
drive label when the drive has been determined to be too small.

Change-Type: patch
Changelog-Entry: Display image size for comparison if drive is too small

lib/shared/drive-constraints.js

@@ -18,6 +18,7 @@
 
 const _ = require('lodash')
 const pathIsInside = require('path-is-inside')
+const prettyBytes = require('pretty-bytes')
 
 /**
  * @summary The default unknown size for things such as images and drives
@@ -376,9 +377,11 @@ exports.getDriveImageCompatibilityStatuses = (drive, image) => {
       message: exports.COMPATIBILITY_STATUS_MESSAGES.LOCKED
     })
   } else if (!_.isNil(drive) && !_.isNil(drive.size) && !exports.isDriveLargeEnough(drive, image)) {
+    const imageSize = _.get(image, [ 'size', 'final', 'estimation' ]) ? image.size.original : image.size.final.value
+    const relativeBytes = imageSize - drive.size
     statusList.push({
       type: exports.COMPATIBILITY_STATUS_TYPES.ERROR,
-      message: exports.COMPATIBILITY_STATUS_MESSAGES.TOO_SMALL
+      message: `${exports.COMPATIBILITY_STATUS_MESSAGES.TOO_SMALL} - ${prettyBytes(relativeBytes)}`
     })
   } else {
     if (exports.isSystemDrive(drive)) {