They must ensure that they have Roblox ... T-shirt will only be shown on the front of the avatar. 512x512 pixels is the optimal image size. Use an image editor of choice to create a design. A ...

A T-shirt is the simplest design to create but fairly basic. Roblox utilizes images in .png, .jpg ... download it to your computer. For each template, notice that the parts are "folded ...

so you'll need to design a t-shirt in an image and then upload it to Roblox. From there, just select it to wear and you're sorted! You'll be best off having a couple of templates for this!