One of the major issues which an author of a children’s book faces is that weather he should hire a Local children book illustrator or any illustrator who can do the job. Although there is no clear answer to this question because the whole issue depends upon the benefit which the illustrations will bring to the sales of the book. Ultimately the book has to sell and illustrations play a major role in determining that.
Any illustration, manual or digital can be transferred online and all publishers are accepting the scanned version of illustrations, given that it meets the basic specifications like 300 dpi and may be other formatting issues like the cmyk format etc. These details may be taken by the printer and it hardly makes any difficulty as the illustrations may be converted to any of the formats. So, the Local children book illustrator factor is over. I have seen the Author and illustrator from different locations, or even different continents working together and making great picture books.
The most important criteria is selection of the illustrator, which largely depends upon the script or the story and in case a Local children book illustrator is available but not suitable for that particular story then there is no point hiring him/her. Also, you should never reject an overseas illustrator only because of the location factor, because in most cases, even the local illustrator will not meet you every day. In fact you will still get the same result irrespective of the location.
The most important aspect is the suitability of the kind of art which will make your story stand out in the eyes of the reader who are mostly the children. The printer does not require the hard copies, he will still scan the hard copies given by your local illustrator, so at the end of the day, your illustrations will be accepted in the scanned format, weather you work with a Local children book illustrator or an overseas illustrator. Look out for established illustrators who have done well in their careers or have received awards, or if you know someone who has real talent and suits your story but is a new illustrator, you may still give him/her a chance.