The recommended image size can differ for each product. The same rule also applies to each available print area, and sometimes, even the item size.
To always make sure that you have your designs prepared in the correct resolution, please refer to the Product Generator.
You can see the exact value for each print area under the Add your design button:
For example, if you switch to the Right Sleeve, the resolution is different:
It’s worth mentioning that this value is that of the highest possible we can produce.
Most times you can go a bit lower but be advised, doing so, may affect the quality of your prints.