A jpg to xls conversion is usually related to either import of pictures to Excel, or in rare cases (OCR) recovery of spreadsheet from previously exported Excel file.
You can import pictures (.jpg for example) to any of the lists in an Excel spreadsheet (.xls, .xslx) as an object. You can do that with most spreadsheets editors as it is one of the most common features.
Some online converters offer this conversion, but they will basically place a picture in empty spreadsheet in most cases.
Updated: April 18, 2017