How to go from this...

...to this!

Open in Photoshop

Turn to Grayscale

Select Levels

Move sliders to adjust light and dark

Until you get pure black and white

Select Magic Wand

Make sure the Contiguous box is unticked

Click on an area of black to select all the black pixels

Copy

Paste

This will have created a new layer with only the black pixels

Select the Marquee tool

Drag a box around your graphic

Crop

Your image is now cropped tighter

Delete the original layer

Make a new blank layer

The new layer will appear above the black pixels one. Drag it down below and call it colour

Now select the Magic Wand. This time make sure the Contiguous box is checked

Holding shift, select the blank areas you want to fill with colour. You'll see a dotted ring appear around those areas.

Turn file back into RGB colour mode

Don't Merge layers

Select the Paint Bucket then the colour your want from the swatches panel

Select the colour you want from the swatches panel, then the Paint Bucket tool, then click in the areas you want to fill with colour

Deselect

Repeat the select and colour process until your image is fully coloured.

Go to Export > Save for Web (Legacy)

Save file as a PNG-8 from drop-down menu. Then set the size to around 1000 pixels wide. Hit Save and name your file.

Upload your saved PNG onto Hotglue!