How to use Smart Objects in Photoshop: To modify the contents of a Smart Object, you can do this manually, one at a time, or you can automate this process. To do this manually, double-click the Smart Object layer, which will open it up in a new tab. You can then place your desired image at the top of the layer stack, size and position it to your liking, then save this tab to update the Smart Object in the main document. Another technique is to simply right-click the Smart Object, click Replace Contents, then select the desired image.
If you’re performing a large number of Smart Object replacements—for example, when creating mockup images—you can save tons of time by automating this process using the Batch-Replace Smart Objects plugin. Simply specify the Photoshop Document To Use, the input folder (which contains your images), and the output folder to save to. Then, just click ‘Run’ and it will automate the creation of all your required mockups. If needed, you can save operations to run later, and you can also chain together as many operations as you need to automate your entire workflow with one single button click.
If you need to create a new Smart Object in Photoshop, you can do that by clicking Layer > Smart Objects, then > Convert To Smart Object, which will perform that action on the selected layer in the document. You can then resize, reposition, and otherwise transform the Smart Object layer to your liking. Understand that Smart Objects act as containers whose contents can be edited. This therefore means that whatever transformations or effects apply to the Smart Object will effectively be applied to the items put inside of it.
