Help turning off auto image download format

somehow I turned on automatically saving download images in .odt format - I really need to turn this off and go back to downloading images in .jpeg. TIA

In your unnamed operating system associate jpg and jpeg files with a graphics editor, e.g. Gimp or maybe a graphics viewer.

Or is it a setting in your unknown web browser?

Please edit your question (click the pencil icon under your question) to add OS and version, how you were downloading the images, and what tool you were using to download them.