Starting from the next release, November 2017, you will be able to embed reports into email bodies. So you will be able to create, for example, an HTML report with the image and embed it into the email body.
From the November 2017 Release Notes:
Embed HTML and QlikEntity report into email bodies
You can embed HTML and QlikEntity reports directly into email bodies.
Recipients will be able to see your data directly, without having to download and open an attachment. QlikEntity reports are embedded as images, and HTML reports are embedded as HTML code. You can embed as many reports as you want, including cycled reports. You can also add text and attachments as usual.
When applicable please mark the appropriate replies as CORRECT. This will help community members and Qlik Employees know which discussions have already been addressed and have a possible known solution. Please mark threads as HELPFUL if the provided solution is helpful to the problem, but does not necessarily solve the indicated problem. You can mark multiple threads as HELPFUL if you feel additional info is useful to others.
Straight answer currently is: NO-you cannot.
You can embed an image using its URL address as a source (it will not come from Qlik report though) and as Ruggero said from next version you will be able to embed a reports in emails body, so you could then create an image as a dedicated report and embed it into your email body.