convert mp3 to mp4 and add picture

[kasfig]

Dear forum members
I would like to take an mp3 audio file and have an mp4 file made from it with a picture of my choice showing when the mp4 file is being played in VLC or when uploaded to youtube.
Please can anyone advise the best way to do it free. I tried doing it with EZ converter online but it didnt work . I suspect the audio file is too long (1.3 hours)
Yours with thanks
Ian

[netmask56]

You can do it all in VLC -
To Manually Add Album Art
Tools > Media Information > "General" Tab >
Right-click on the proxy (default) orange cone picture (1" x 1", on the bottom right)
> Select "Add cover art from file".
> Change any value (e.g.: the Artist), only then the 'Save Metadata' button will appear, after it does - press it.

[Cornucopia]

No need to convert/re-encode. Mp3 already has the ability to insert a picture into its header/footer (usu. referred to there as "album art"). Use mp3tag.

Scott

[kasfig]

Dear Netmast and Cornucopia
Thank you for your most helpful comments which are in themselves truly instructive and useful!
However my desire in regard to these mp3 files is actually to convert them into mp4.
The reason I would like to do this is so that later on I can add subtitles.
Upon turning them into video I would be keen to have a photo showing whilst the video is playing.
Your kind advice in this would be much appreciated
Ian

[teodz1984]

Use the software like http://www.photodex.com/proshow
Select pics select background music
output as mp4,

[kasfig]

Dear Teodz
Thank you for your kind suggestion.
I am certain this software would produce the goods. I notice it is available on free trial basis
I am sure one has to then purchase the package to continue using it.
I wonder whether there might be some restriction in the trial version
For example (maximum length of audio)
As an alternative please can anyone suggest a free piece of software that might help.
Ian

[teodz1984]

https://alternativeto.net/software/proshow/

[kasfig]

Oh - thank you so much: I appreciate your kindness I will have a look
Ian

[netmask56]

What you really need to do IMO is first make a video file, MP4 or whatever and then simply add the MP3 audio file you have. So you are not "converting" a MP3 to MP4 but it is the other way around. Create your video first and then add the audio.. As an example in Womble you can drop a still into it and then drag it out along the time line to the length of the existing audio, add the audio to the audio time line and save... There are other programs to do it...