Crop empty browser chrome before resizing, but leave enough surrounding interface to show where the problem occurs. Use Image Resizer and inspect the smallest displayed preview: error text should still be legible without excessive zoom.
Remove or obscure account names, tokens, addresses, and notifications before uploading. Save the original privately in case someone later needs a closer look. If one image cannot show both context and detail, use two labeled screenshots.
Which part of the screen must readers be able to read?