Please oh please oh PLEASE put your refs on your canvas.
Put 'em on a separate layer, draw on top of them, move 'em around, scale 'em, erase 'em if you have to, but PLEASE put your refs on your canvas it makes things so much easier.
I use this app called vizref
It's amazing for this exact thing! You can host as many gifs/images as you want, organize your canvases for easy reference, I use it often even when I'm doing physical art, it's incredibly useful to me for moodboards too!

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