Even if you hired an actual programmer, it'd take a massive amount of time to build a Photoshop clone.
Of course, at the end Photoshop is lines of code and it could be output as is, end to end. One problem is that users aren't generally giving very precise design documents which would narrow the way to interpret them into code in precisely one way. Or that a design document at any level of precision, other than code, couldn't be interpreted in multiple ways when it comes to a specific implementation.
LLMs also take a relatively long time to output acceptable code, often taking tens of minutes before giving you a small diff. The larger the codebase, the longer it usually takes to start producing code, even over an hour.