Help with consistent image sizes

Hi there,

I am very new to square space and have just downloaded the free trial.  I am trying to re-sizes my images so they look constant.  When I uploaded an image, in the shop the image looks ok as a listing but when you click on it to see the full details of the product it distorts.  Is this because I am in a trial version?

Also is there anywhere that I can change the $ to £s in the eCommerce section - again is this because I am on a trail?

Excuse my ignorance, this is the first time that I have used a platform like this so any help is much appreciated 🙂

Thanks,

Antonia