Max file unique renaming?

I have a file upload field where people can upload images to a database. Typically there is no issues with a unique renaming function, however i have run across an issue with a file named image.jpg

since this is probabaly a common name of a file to upload, it seems recently that i am getting a renaming error whenever this file name is uploaded

here is the message i am getting
Couldn't create a unique filename. F:\***\patient_images\image_1000.jpg

seeing that its at 1000 for the renaming option, is this the max that the system will generate a new filename?