AP91172

In the Pixel Persona you can use the Selection Brush Tool to select the white background. If the image has been rasterized (i.e the layer is showing in the Layers panel as a '(Pixel)' type rather than an '(Image)' type) then pressing the Delete key will delete the selected white areas.

Rightclick on the layer and choose to rasterize. 

Hi aP91172,
Welcome to Affinity Forums :)
Take a look a this video tutorial to understand how to work with selections on raster images (like the JPG on your example). Although the video is for Affinity Photo (our photo editing app) it works the same way in Designer in Pixel Persona (you can change to Pixel Persona going to menu File ▸ Personas ▸ Pixel on Windows or Affinity Designer ▸ Pixel Persona on the Mac).

If i have a jpg. picture. No layers, just background= pixel layer.
I use the selection brush and trace around the object I want to keep.. (or the other way around and invert the selection (sometimes it's easier that way). If I zoom in, it's easier to select
 
I then click the delete key and the selected parts appear with a checkered pattern.
 
 
However, if I export this result as a jpg. or another format  that doesn't support transparency, the parts that you selected and deleted will be white.
 
Is that what happens to you?

Hi AP91172

I am not aware of any issues saving in Affinity Designer, could you provide a screenshot of what you're seeing when you attempt to save?

We are pleased to announce the first update for Affinity Designer for Windows (version 1.5.1).
 
The update is described here and can be downloaded from here. Once downloaded, close Affinity Designer and run (double click) the downloaded EXE to install it.
 
To install this version you will need to have the Affinity Designer for Windows already installed OR you will need to type in your email address and a valid Product key when prompted. When installing on top of an existing version you will not be prompted for the product key. If you need it you can find your product key (and a download button) in your Affinity store account, where you will also find the email address used to generate the key when you ordered the software. 
 
If you have installed any previous beta version of Affinity Designer 1.5.0 or 1.5.1, it can be safely uninstalled before or after installing this release update, they are independent installs. The beta will stop working soon anyway.
 
Please report any problems you have installing or using this new version in the Windows forum here
 
Patrick Connor
The Affinity Team

Hi Appogee.
 
Did you notice that there is now an eyedropper (Color Picker) tool in Affinity Designer (& I think one in the recent betas of Photo)? It does not work exactly like in other graphic apps so it still may require some experimentation to see how to use it.

What Affinity application are you using?

Hi everyone,
 
I've just put three tutorials on YouTube aimed at complete beginners, although slightly more experienced users of Affinity can get something out of the third one.
 
So here they are:
https://youtu.be/mYwjdx9FJRA- Affinity Photo Tutorial for Beginners - 101 - don't panic!
https://youtu.be/_sbuSNiiZWc- Affinity Photo Tutorial for Beginners - 102 - What is a Layer?
https://youtu.be/aWx4X-Nes-s- Affinity Photo Beginners 103 - 5 Essential Photo Editing Steps
 
If they are of some use to you then it's all good.
 
Cheers,
Simon Foster