Open a screenshot or a photo in the Chrome side panel, blur the whole image or drag a box over the parts you want hidden, then save or copy the result. Everything runs on your own computer: no upload, no account, and the file keeps its original format.
Open an audio file, drag the two handles across the waveform, and export just the part you need as MP3 or WAV. Decoding and encoding run on your own computer, so nothing is uploaded, there is no account to create, and the clip has no watermark.