1.4.1 Non-Conformance Shown with Non-Technical Explanation
The image of tulips fails conforms to 1.4.1 because though alt text exists, it does not include each of the colors that would easily identified by a sighted user.
1.4.1 Non-Conformance HTML Markup and Technical Details
The following HTML markup begins on line 30 of this page:
<img src="tulips.jpg" class="nondecorative" alt="tulips of different colors">
The alt attribute includes the detail of tulips but not the tulip colors.