Is there a way to convert a picture that was saved as an eml to another graphic form, such as a jpeg or bitmap, so that it can be worked on (cropped, etc..) in an image program?

If the image is an attachment, just "Save attachments as" on your desktop. If the image is embedded into the eml than basically make a PDF of the file by using a postscript printer driver to "print to file" then drag that file over Adobe Acrobat distiller to create the PDF or send that file to https://createpdf.adobe.com/ then export out as .jpg. You may be able to bring that .prn or .ps file up into Photoshop if you have it. OR just simply take a screen shot of the email (Alt+Print Screen and paste that into Paint save aas bitmap then bring up into you image editor.

Whoa, there! Eml is markup language, not a graphic format. If you're referring to a Hotmail eml, guess what - some of them are actual Extensible markup Language files, while others are... wait for this: Unix-to-Unix Encoded (uue)! Really! Some of Microsoft's Hotmail is handled through Unix... go figure! If it is the last-mentioned case, add-or-replace the extension to uue, and Winzip will decode it (2 files, one is a pretty useless text file, the other is THE REAL THING!). On the other hand, sometimes downloading/saving one of the screwed-up Hotmail eml files is a bit of a struggle... but I a ssume from your post that you already have this eml saved to your HDD.

Right click on the image and select save as.