Lightspeed Onsite uses a default image size of 512 pixels by 512 pixels. Accumula's Magento 2 Integration will upload the maximum image size stored in Lightspeed Onsite for each image. You can find the High Res Images switch on the Advanced tab in Accumula Settings.
In order to provide a consistent online shopping experience, you will want to be consistent about the image sizes imported into point of sale and thus to Magento 2. We recommend consulting your designer about optimal image sizing.
Notes About Images
Accumula cannot delete images from Magento 2. If products in Magento 2 already have low res images associated, we recommend deleting the low res images before adding High Res Images to POS. After turning High Res Images On, Products in Lightspeed will need to be updated/resaved. We suggest testing high res image publish on a few products first. Once tested, we recommend deleting low res images from Magento 2 and performing a Bulk Update in Lightspeed to publish the high res versions of the images.
Saving high res images in Lightspeed Onsite will increase your Lightspeed Onsite database size and the time it takes to perform Lightspeed Backups and Restores.