How easy to indentify memory like ROM or EEPROM Flash Memory Areas of a Chip
On a chip ALL LAYERS are used for ALL structures. All layers are needed to make the components (transistors, diodes, resistors, capacitors) and connect them. The difference with memories can be seen because memories require very regular structures.

(source: zeptobars.ru)
Note how the above photo of the LM1117 (from Zeptobars, CC Attribution 3.0 Unported Licence as noted on Contacts page) — it's a voltage regulator, it has no memories — is &quot;messy&quot; at the bottom. The only regular structure is at the top which is probably the output transistor.
Note how the MT4C1024 DRAM below (also from Zeptobars) has very regular structures (RAM) but not at the edges, these are the drivers for the memory.

What you see in the photos (thanks to the link to a Zeptobars article provided in pjc50's comment) are the connections between the components. The components themselves are under these connections. They are usually too small to see even on these micro photos.