Won't save as a PNG

[sheeshshe1]

Hi, I am not very experienced in photoshop... however, I am always making the same product images for my website. I do them the same way every time, just with different combinations of images. Every now and again it will not let me save it as a png as there isn't the option to do so. If I save it as a jpeg the file ends up being much too large and I can't use it on my web cart. It makes me wonder if something weird is happening to the file when I am working on it and the file is just too large of a file? Is there something I can do to figure out what is going on? it is just very strange and I am getting frustrated with it. Thank you!

 

[Steve]

Make sure you're in RGB mode.

 

[sheeshshe1]

THANK YOU!!! That worked! How on earth did it get in that mode anyways? I never changed it... so strange!

 

[Steve]

Very good, I'm glad that fixed the problem.