Using Slice in lectures

September 26, 2014

Slice is a useful tool for showing biomedical images in lectures, particularly when;

  • The image is large and you can’t show it all at a suitable level of magnification
  • You want to make the image easily accessible to your students in a resolution that is superior to what they will get from a PDF of your PowerPoint slide
  • You want to include annotations that guide your student as to relevant aspects of the image, and to be able to reuse those annotations in other contexts

In image based disciplines, a very common complaint from students is that while the lecturer points to things on the image during the lecture, they are never sure what exactly was referred to later. And annotating a PowerPoint PDF is limited in various ways, and can’t easily be reused. This is another way that Slice can help!

A simple example

I want to show a microscopic view of some condition. From Slice, I can find a good example field, make a screen clipping of the image, and past into my PowerPoint (shown below in the traditional way, using the Windows Snipping tool).

Now, by adding the URL for that image to the hyperlink field in the PowerPoint image, I can make the image “clickable”.

During my lecture in slide show mode, if I click on the image, it will open in a separate browser, and then I can look at the image “live in the class”. You need an internet connection of course! Also, the browser can take a little while to open first off, but you can just leave it in the background for the rest of the lecture, and subsequent images open up much faster (or you can open it beforehand). Sizing the browser so it’s just a little less than full screen makes getting back to your PowerPoint very simple.

The benefit of adding that hyperlink is that if you give that PowerPoint to your students (either as is, or in the form of a PDF file of the slide set) then when they click on the image at home for revision, they will see the same image as you. To do this, it’s best to SAVE the file as a PDF, rather than PRINT as a PDF – the latter may not preserve the hyperlink.

Slice offers quite a bit of control over exactly what you see in the browser when you click on the hyperlink. You can just show the image, or you can show a certain part of the image at a certain magnification, or you can show your layer containing lots of your annotations that you want to share with your students only, or you can open Slice so that just one of those annotations is highlighted). The choice is yours, and depends on your educational needs. The details of how to grab the right URLs to show these different views of the images and layers is described elsewhere.

Managing hyperlinks

One of the problems with this is that the hyperlinks in Slice can get very large! That’s not a problem if you can add them to the hyperlink field of a PowerPoint or some other object like text, but its often easier to show people a simple URL. Fortunately there are lots of services (, bitly, etc.) that can take a gnarly URL like and beat it down into something like This is the sort of thing you can place as text on your PowerPoint slide with the image, and that anyone can enter via a keyboard. So that even if the student only has a paper copy of your lecture notes, they can quickly find the image you used in the lecture. These sites often have the advantage of letting you see how many people have clicked on your image using that shortened URL (and when and from where). They will even generate a QR code for you if you want it!

Using your annotations again in other lectures

Having spent some time making an annotation (or perhaps duplicating it from your colleague), it’s good to be able to use it again. Clearly you could just use the same URL in different lectures. However, Slice lets you easily DUPLICATE a layer, and then save it as another name. So for instance I can name one layer as “Image for bowel cancer for use in Neoplasia lecture 2014”, then duplicate it and rename it with an entirely new title. Why would I bother? Firstly because I can edit the image annotations – maybe to show other features more relevant to this different audience, while keeping most of the annotations the same (here I have removed the mark up of the lymph node containing cancer, and added a link to the same slide stained with an antibody to P53). Also, I can create a new short URL for this layer (in the case above its, and I know then that people looking at the new image are following it from the science lecture, not the medicine one.

I’m sure there are lots of other ways that you could use Slice in lectures, but these are a few suggestions that might get you started.