Upscaling, resizing and mock ups

​@Bobbydazzler 

You need to first ask yourself why you wish to upscale, as you may not need to. And if you do, you probably want to do so on a copy of the original.

For example, there's a fallacy that all print files need 300 PPI (not DPI) print resolution. Although often quoted, this is blatantly incorrect and misleading.

https://community.adobe.com/questions%2D712/photo%2Dblow%2Dup%2Dquestion%2D1162192

If you're a member of LinkedIn, then I highly recommend the following post, which is in French, "300 DPI: the cult of useless pixels":

https://www.linkedin.com/pulse/300-ppp-le-culte-des-pixels-inutiles-branislav-mili%25C4%2587-1qx6f/

As ​@D Fosse wrote, you can record an Action using Image Size or Fit Image or Generative Upscale, then you can use Batch to run the Action (or a script like Image Processor). You can even batch resize using Adobe Camera Raw (ACR) for supported file formats. There’s also ACR “Super Resolution” and neural filter options as well (slow).
 

Keep in mind that you may burn through your generative credits on batching Generative Upscale.

As for upscaling “increasing the quality”, that’s very much dependent on variables such as the original image pixel dimensions, lossy compression or noise, the resize scale factor and the algorithm… Not to mention the output method and viewing conditions.

Bulk/batch mockups depends on many factors as it’s generally dependent on how your file is set up and the replacement files in order for a script to process the files. There are probably hundreds of posts on the forum on this topic, all you need to do is search the forum to start.

You can batch/bulk anything in Photoshop with actions, as long as the processing steps are determined.

For conditional and more advanced processes, Photoshop can also run scripts. This forum has several regular participants well versed in scripting who can help you, if you describe what you want (not me alas).