Project Gutenberg does have illustrated versions in HTML and PDF format.
Dik Trom's dad keeps repeating about his grand-son as he did about his son: "He is a special child--and that he is". Obviously, master Kieviet was trying to get the laughs of his pupils with this running joke of the first book, and that grates a little.
Other than that, this is a fine book in the classic Dik Trom series, full of adventures.
Interestingly, this book was censored by the Nazis during the occupation of the Netherlands, and according to http://www.xs4all.nl/~jikje/Verbod/Boeken/trom.html the censored bits were never changed back, so this may be the first time you read the original version.