Using images

In this JungleMail for Office 365 tutorial, you will learn the basics of adding, uploading and editing images. 

Image optimization guidelines

Here's a couple things you should consider before adding images in your newsletter.


Make sure that images look good on high-DPI displays, or retina displays. A good idea is starting with an image that has a resolution of 72 DPI. When it comes to image width, 600 pixels is a good midle-of the-road choice that works well across email clients - but to make the image look sharp, the original should be 1,5x or 2x larger. For example, if you want to have a 600-pixel-wide image in the newsletter, use the original with at least 900 pixels, and then resize to 600 pixels in Drag & Drop Builder (instructions below).


You can find image compressor tools online to help resize image without losing quality. This is also known as lossless compression, and there are quite a few algorithms to achieve it. For example, the Deflate algorithm grabs duplicate strings of data (pixels) in the image code and sets a “pointer” for each duplicate. This duplicate is then replaced with a symbol that compresses image date. No pixels are deleted or forced to change color in the process. The resulting image is identical to the original, but the file size is smaller.

Another option is to use lossy compression which reduces image file size even more than lossless compression. However, this is achieved with a loss of quality that in most cases is irreversible. 

Most compression tools will let you choose the degree of compression that will be used on your images. If you want the best balance between optimization and picture quality, we recommend this option.

Linking vs. embedding

When you add an image to a newsletter in JungleMail for Office 365, you're actually adding a link to the image HTTP address. When a recipient opens the newsletter, the image is downloaded. A big advantage of linked images is that they keep newsletter size down because they do not travel with the newsletter. Just keep in mind that if the linked image is very large, it might take some time to load in the newsletter, especially in areas with slow internet.

The real downside is that to prevent spam, most email clients block external images. This limitation can be bypassed by inserting images directly in the newsletter by using CID embedding or inline embedding. Both methods require require advanced coding knowledge, with mixed results. The majority of email clients that reliably display embedded images (e.g., iOS Mail) don’t block images by default, making this technique redundant.

Adding images to a newsletter

From the gallery

1. Add an image block to the template or select an existing one, and click Browse.

2. In the image gallery, hover over the image you need and click Select.

Alternatively, you can Drag & Drop images into email body directly from the gallery.

Via image URL

1. Add an image block to the template or select an existing one.

2. In the URL field of the block settings, enter a public image URL address.

Adding images to the gallery

1. Open the Gallery tab.

2. In the gallery, click Upload images.

You can also drag and drop an image or multiple images into the gallery from your computer.

Adding a background image

1. Select a section, go to the  Style tab and switch the Background Image toggle to On.

2. Click Browse and select the image you want to add to the background. Check the boxes below if you need to make further adjustments to image style.

Please note that not all email clients support background images. If that happens, the section background color will be displayed instead. Make sure this color works well with the rest of your content.

Image editing

1. Select the image block and click the  Edit icon on the upper right corner of the block. You can find the same icon while hovering over the image in the gallery, too. Another option is to click Edit image in the Content tab.

On the left sidebar of the image editor, you will find 7 tabs, allowing you to quickly change the general look and feel of the image and to see the results instantly.

  • Transform: change image size and aspect ratio
  • Filters: add filters (Black & White, Vintage, Cold etc.)
  • Adjust: change brightness, saturation, shadows etc.
  • Focus: add focus (radial, linear etc.)
  • Text Design: add text and text style
  • Frames: add frames (Wood, Art Decor etc.)
  • Overlays: add overlays (Clouds, Paper, Bokeh etc.)

2. Feel free to combine different effects and revert changes with the Undo button. Once you are happy with the result, click Save.

Width options and resizing

Resizing in Drag & Drop Builder

When you add an image to the layout, it is automatically resized to fit column width. To change image width, take the following steps:

1. Select the image and open the Style tab.

2. Turn off the Automatic resize image toggle.

3. Enter image width in pixels (aspect ratio is locked, i.e., height is changed automatically).

It is important to note that this method only changes image dimensions in the newsletter body, while the actual image size remains the same. Also note that you can only make the image narrower but not wider than the default block width. 

Automatic image resize

When this feature is enabled, JungleMail for Office 365 will pick the best size for the image based on a combination of image width and the available space in the layout:

  • Large images, wider than the available space, will be set at 100% width and will keep this ratio on mobile, using the entire device display width.
  • Small images, smaller than the available space, will use the image natural size to avoid distortion effects or blurry pics.

Full width on mobile

When you turn on this feature, the image will use the full width of the mobile device screen.

Resizing in the image editor

1. Select the image, then click the Edit image icon in the top right corner, or click Edit image in the block editor.

2. In the editor, select the Transform section. At the bottom, select Lock Resolution and enter width or height.

3. In the top right corner, click Save.

This method creates a copy of the image with the new dimensions in the gallery and uses this copy in the newsletter. You may notice that pictures resized with the image editor look slightly sharper around the edges. However, there is also more image noise. Experiment with both resizing methods to find the one that works for you.

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