Before you get a drawing or painting commission...
Here are a few things you can check in your picture reference to ensure best quality artwork.
(Pictures used below are stock photos and are used as visual examples. I do not own the below pictures.)
1. Picture Resolution
Images from Social Media? The images you would see on a website or social media are generally quite small; these platforms automatically reduce image size when you create a post for faster loading. Images from these sources are not the best for artwork commissions. While they may work for smaller sizes, they'll not promise best results in the finished pieces. Since the image itself is not detailed enough for the artist to work from, the artwork will not be the highest quality.
Images directly clicked from phone or a camera? Modern phones are capable of clicking highly detailed images with stunning resolution. If you have a picture that you clicked with a modern phone or camera, they will be great resolution. These images can be used for both artwork commissions.
2. Colour Contrast
Next thing you would want to check in the picture is the colour contrast. While most artists have tools and skills to be able to fix contrast, it is best to pick a picture that has good colour contrast. This will make sure the subject of the painting or drawing does not look faded/hazy.
3. Lighting
Lighting plays quite an important role in artworks whether its drawing or painting. It adds volume, depth, and movement to the composition. Its extremely important that the image reference you provide has the subject in good lighting; the important features of the subject should be visible to the artist and the artwork will also represent the same. Some artists are able to find a work around but to get the best results in the artwork, choose a picture where your main subject is clearly visible. If you have a uniquely photographed picture and like way the lighting is in the picture, you can check with the artist on how it will impact the quality of the artwork.
4. Composition
(Original Image by Edu Carvalho on Pexels)
The image of this elderly woman has been adjusted on the right to show you how composition can change the way an artwork piece will turn out. The left is a great photograph and is well detailed. However, for a commission, the image on the left is highlighting the overall theme and would not look as effective since there are a lot of competing elements in the picture. The picture on the right is zoomed in a bit and allows the portrait of the lady to be the main focus of the composition. Work alongside the artist to figure out what's the best way to place the subject in the artwork. This may mean suggesting the artist to remove the background, crop the picture a certain way, remove unwanted objects, zoom in, zoom out, or rotate the image a certain way. Artists have a great vision for composition so bring it up with them on how the image may be used to get the best artwork composition.
Hope this helps!