For images 500 pixels or less in both width and height.

Posting low resolution images is generally discouraged, unless no higher quality is available, and the image itself is reasonably exceptional and/or the image is intended to be low-res (e.g. pixel art).

You can also search for images by resolution, e.g. width:>=3200

See also:

• thumbnail (≤ 250×250)
• low_res (≤ 500×500)
• hi_res (≥ 1600W / ≥ 1200H)
• absurd_res (≥ 3200W / ≥ 2400H)
• superabsurd_res (≥ 10000×10000)
• pixel_(artwork)
• wallpaper