In my opinion the large number of fields is overkill. The best database table design is when there is nothing left to take away, not when there is nothing left to add. Consider the poor son-of-a-gun (you) who has enter all this data!
The core or main table should not be more than 20 fields. Since it is a relational DB, you can always add additional tables over time. I am unsure what 'drop down' has to do with the database design, a drop down component is an interface element.
You will also need to consider 'data types' when you design the tables; like most things in life there are trade offs with each decision. Unlike spreadsheets, database maintain rigid adherence when entering data; if the DB expects a date then you cannot enter a ???? for the year (if it is unknown). You can establish a value field as a number of numeric data types including specific types like 'currency'. Read up on each data type and understand the pros and cons for the type, do not blindly choose them.
I would start with the establishing the core table and perhaps 2-3 additional tables. I would populate it with a few hundred stamps and then move on to the interface (data entry forms and reports). Make the implementation decisions (platform and tools) and develop your first data entry form and a few simple reports (which would be based upon queries in the database).
When you get to this point, you will have learned a number of things which will facilitate adding additional tables and making your forms and reports more powerful. The last thing you want to do is enter lots of stamp data and then realize you need to make foundational changes to the way you designed the database tables.
A simpler 'main' table with multiple related tables allows for better performance and much more flexibility. For example, rather than having an image field (and I do not recommend storing images in the database but rather just storing file paths to the image file) I typically use a separate 'link' table. The 'link' table supports either absolute or relative links. If you decide to add another image field (perhaps for the stamp back, covers, etc.) or if you want to add a link that returns all eBay
'sold' values; you simply add another field to the 'links' table.