GRB is a raster image format associated with two calculator models produced by Hewlett Packard in the 1990s: the HP 48 and the HP 49. Both could be used for advanced algebraic operations and calculations and were considered innovative at the time of their release. GRB images most likely contain screen caps or other type of data connected to these devices. They are rare and difficult to open with regular image viewers.
The quick and simple way to handle your files is to get a quality piece of software, such as reaConverter. This software is extremely efficient in managing a wide range of batch conversions. As you will soon realize, reaConverter will help you avoid spending countless hours trying to figure out how to convert multiple GRB files as once.
JPEG JPG PNG GIF TIFF TIF BMP ICO EMF WMF AI PDF EPS PS EPI WEBP WEBPLL JP2 PCX TGA DWG DWF DXF DGN WMZ CGM DRW SHP GBR PCT MIF PLT PCL SVG WPG CIN DCX DIS HRU MTV PRC RAD PIC RLA QRT SGI XBM XPM SWF CAL FAX FITS PSD PGM JXR BPG APNG DDS SVGZ CG4 FLIF AVIF