[glesica]

I haven't used Photoshop in quite a few years, but I'm pretty sure it works (or worked) the same way as Gimp. Maybe people who do a lot of work in image editing software are accustomed to this workflow? It seems reasonable, since exporting flattens layers and such, which a professional would probably want to preserve (and may not want to risk accidentally losing).

[Ralfp]

In PS you have "save as" dialogue in which you pick extension, and "save for web" which additionally lets you fine-tune optimisation.

In gimp ctrl+s brings you "save image" dialogue that explictly forbids you from saving anything but XCF, which I too find very annoying when doing quick fixes in batch of graphics that don't have xcf source.

[rhizome]

I've taken to using the "File > Overwrite $filename..." option.

[noamyoungerm]

IIRC, the workflow in Photoshop is this: If you open a photo file, and when you press save there is only one layer in the file, pressing ctrl+s will not change the file format. Generally this means that minor changes (crop, recolor) preserve file types, while larger ones require you to export.

[Drdrdrq]

I don't use PS, but in my use case this behaviour is really annoying. Maybe I am not their target user, I don't know - the problem is that Gimp is really nice piece of software and it is exactly what I need.

I am baffled why they changed this and why they stick to this decision. But it looks like there is a plugin which fixes that (see one of the other answers), so - yay! :)