A jpeg to pptx conversion is actually standard workflow done in Microsoft PowePoint or any other presentation software with PowerPoint format support. You should be able to import pictures such as JPEG file (.jpg, .jpeg) and use them on one of the slides in he presentation (.pptx).
Convert JPEG bitmap image format to Microsoft PowerPoint Open XML presentation.
We have found one software suitable in our database for this conversion.
Microsoft Windows software - convert jpeg to pptx on Windows
Visual processor used to create high quality presentations, charts and graphs
Convert from jpeg file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.