Where to find rapidly released space image data

I post a lot about processing the image data returned from spacecraft into gorgeous space photos, such as this one:

For those of you who are interested in checking out this exciting hobby, following is a list of many current data sources for rapidly released planetary image data. You may also want to check out my explainer on data types and software tools, my space image processing tutorials, and the work of amateur space image processing enthusiasts.

Missions that release image data directly (or nearly directly) to the Internet upon receipt from space

• Mars Exploration Rover Opportunity: Data from all rover cameras (Pancams, Navcams, Hazcams, and Microscopic Imager) are converted to JPEG format and automatically contrast-stretched before release. Also available through Mike Howard's Midnight Planets and Mark Powell's Mars Images app
• Mars Express: Data from the Visual Monitoring Camera are available in two ways. Science-quality data as received from the spacecraft are available via the VMC data archive, while processed PNG-formatted versions are available via the VMC Mars Webcam Flickr page.
• Cassini: Data from the Imaging Science Subsystem's Wide-Angle and Narrow-Angle Cameras are converted to JPEG format and automatically contrast-stretched before release.
• Curiosity: Data from Navcams, Hazcams, MAHLI, and ChemCam are available immediately; data from Mastcam and MARDI are available after a 24-hour delay. All are converted to JPEG format and automatically contrast-stretched before release. ChemCam images are also flat-fielded. Mastcam images are highly compressed, reducing their quality. Also available through Mike Howard's Midnight Planets and Joe Knapp's Curiosity Rover Images and Rover Image Synth.
• Any Hubble Space Telescope images that are taken as a result of a request for Director's Discretionary Time are released immediately, in science-quality format. (I suggest reading this tutorial for guidance on using the Hubble data archive.)
• I don't usually cover solar missions, but SOHO, SDO, and STEREO all share science-quality data immediately.
• I'm also not familiar with all of the realtime Earth image resources, but notable ones include DSCOVR and Himawari for full-globe views. More detailed views from Terra, Aqua, and Suomi NPP are available via NASA's Worldview interface.

Missions that release image data in batches within weeks of receipt from space

• New Horizons: Data from its Long-Range Reconnaissance Imager are released on Fridays, with each release including images returned as of the preceding Tuesday. Images are converted to JPEG format and automatically contrast-stretched before release. This mission is almost done returning all its data.
• Juno: Data from JunoCam are released at weekly intervals, including data about a week to two weeks old, in a couple of formats. Right now and through October they are working on a "Marble Movie" with frames appearing at this buried location roughly once a week. When I notice that they have appeared, I download and repost them here.

Missions that do very rapid (within weeks to 3 months) release of science-quality data

(Apart from the ones mentioned above)

• Rosetta: Navcam releases its science-quality data in monthly batches, with the most recent images being less than a month old. Sadly, that mission ends next week.
• Mars Reconnaissance Orbiter: HiRISE releases science-quality data in quarterly batches, with the most recent images being about a month old. You can browse it in their HiRISE image catalog, or use the map interface at ASU.

All other NASA and ESA planetary mission data becomes public eventually, typically released between 6 and 12 months after acquisition, to NASA's Planetary Data System or ESA's Planetary Science Archive. There's a bit of a learning curve involved, but it can be really rewarding to dig through these archives. Here's an introductory explainer on the PDS.

Go forth and enjoy all the pretty pictures!