The developers "fixed" this by making it incredibly hard for people using Gimp for simple, quick image editing tasks to tell if they've saved their work at all. The dialog warning you that you're closing an image you've forgotten to save anywhere since the last change is almost identical to the one warning you that your only copy is in a non-native format. It does this even if you lost absolutely nothing by saving back to the original format, which is often the case.

The alternative is to remember the format the image was loaded from, track all of the features of each individual format, note when the user changes something that can't be saved in the original format, then before the user "saves" in yet another format decide when to pop up a dialog that describes how these featuresets overlap and alternate ways to "save" that might preserve more or fewer of them.

All of this to avoid saying: "You're converting your working copy into a lossy format. You might lose things."

No, I'm not, since I know what I am doing.

I know what I'm doing, too. Thus, I can learn to use another menu item to do what I want.

The save vs export change only hits against habits. It took me a while to figure it out at the time but these days I practically only ever use "Export as" because I know what I want and I know what I'm doing, and how to do it in later Gimp versions.

While I didn't like the change it does make sense. Loading and saving in Gimp is about native formats. Saving to a bitmap format loses much of the data so calling it an export is quite appropriate. Before, Gimp was always nagging about whether I'm sure I want to save as jpeg because I wouldn't be saving my Gimp state that way. That wasn't pleasant either.

Even if you use Export to save, GIMP will complain that you didn't save the image you just saved because you wanted to use a format others can open as opposed to the format it wants to push.

It is not a major issue, but it still is an annoyance you have to face constantly if you want to work with other file formats directly as opposed to treating them as second class citizens regardless of what sort of editing you are doing.

If you save a png to a jpg, you'd expect a warning. Saving an image that you're working with to a standard image format is a lossy conversion.

It is not always a lossy conversion, e.g. saving a GIF image to a PNG image is a lossless conversion. If the operation is lossy then show a warning (assuming you haven't already shown a dialog like GIMP's file format dialogs), if the operation is lossless then there is no need for such a warning.

Similarly if you are editing an image with a single layer (the background) and save it as a PNG it is always lossless (no need for warning dialog) but if you add a layer and try to save it then it becomes lossy (so show a warning dialog with the option to proceed as the default - being default because that is what the user asked for - and an option to save as XCF instead so that the layer is preserved).

What about beginners?

They will eventually stop being beginners.

However beginners or not, unless your primary file format is XCF, GIMP will always annoy you about not saving your image even though you did it - just instead of saving it in its own proprietary format that nothing else supports, you saved it in something that can actually be shared.

Never annoyed me. I was too busy appreciating how good free photo editing software is.

Well, it annoyed others, that doesn't mean they cannot also appreciate how good GIMP is. It isn't like you can either like ALL aspects of a program or NONE with nothing inbetween.

Beginners won't do anything to their images that would necessitate any other format than JPG. Otherwise they wouldn't be beginners. I've now got over a decade experience with Gimp and I still don't need anything other than JPG.

You should try layers; they're really useful.

I can't think of a single use case for layers, to be honest. They only ever annoyed me, because I had to switch layers for editing some things that were automatically their own layer, like text.

Wouldn't it be fun if, like some other image editors, GIMP would merge newly created text into the image and make the text non-editable? :) So much simpler!

I'd prefer that behavior.